Granite ndi mtundu wa miyala ya igneous yomwe imakumbidwa chifukwa cha mphamvu zake zazikulu, kuchuluka kwake, kulimba kwake, komanso kukana dzimbiri. Koma granite imagwiranso ntchito mosiyanasiyana - sikuti imangokhala ya masikweya ndi ma rectangles okha! Ndipotu, timagwira ntchito molimbika ndi zigawo za granite zomwe zimapangidwa m'mawonekedwe, ma angles, ndi ma curve amitundu yosiyanasiyana nthawi zonse - ndi zotsatira zabwino kwambiri.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ makina opangidwa
■ yathyathyathya bwino ikadulidwa ndi kumalizidwa
■ osagwira dzimbiri
■ yolimba
■ nthawi yayitali
Zigawo za granite ndizosavuta kuyeretsa. Mukamapanga mapangidwe apadera, onetsetsani kuti mwasankha granite chifukwa cha ubwino wake wapamwamba.

ZOFUNIKA KUGWIRA NTCHITO MIYEZO / ZOVALA KWAMBIRI
Granite yomwe imagwiritsidwa ntchito ndi ZHHIMG pazinthu zathu zodziwika bwino za pamwamba pa mbale ili ndi kuchuluka kwa quartz, komwe kumapereka kukana kwambiri kuwonongeka ndi kuwonongeka. Mitundu yathu Yakuda Kwambiri ili ndi kuchuluka kochepa kwa madzi, zomwe zimachepetsa kuthekera kwa ma geji anu olondola kuti azizizira mukayika pamapepala. Mitundu ya granite yomwe imaperekedwa ndi ZHHIMG imapangitsa kuti kuwala kusamawonekere kwambiri, zomwe zikutanthauza kuti maso sagwira ntchito bwino kwa anthu omwe amagwiritsa ntchito mapepala. Tasankha mitundu yathu ya granite pamene tikuganizira za kukulitsa kutentha kuti tichepetse izi.

CUSTOM APPLICATIONS
Ngati pulogalamu yanu ikufuna mbale yokhala ndi mawonekedwe apadera, zoyikamo ulusi, mipata kapena makina ena, muyenera kusankha chinthu monga Black Jinan Black. Zinthu zachilengedwezi zimakhala zolimba kwambiri, zimateteza kugwedezeka kwambiri, komanso zimathandizira makina kukhala bwino.

Ndikofunika kudziwa kuti mtundu wokha si chizindikiro cha momwe mwalawo ulili. Kawirikawiri, mtundu wa granite umagwirizana mwachindunji ndi kukhalapo kapena kusakhalapo kwa mchere, zomwe sizingakhudze makhalidwe omwe amapanga zinthu zabwino pamwamba pa mbale. Pali granite ya pinki, imvi, ndi yakuda yomwe ndi yabwino kwambiri pamapepala apamwamba, komanso granite yakuda, imvi, ndi pinki yomwe siiyenera kugwiritsidwa ntchito molondola. Makhalidwe ofunikira a granite, monga momwe amagwiritsidwira ntchito ngati zinthu pamwamba pa mbale, alibe chochita ndi mtundu, ndipo ndi awa:
■ Kuuma (kupotoka pansi pa katundu - komwe kumasonyezedwa ndi Modulus of Elasticity)
■ Kuuma
■ Kuchulukana
■ Kukana kuvala
■ Kukhazikika
■ Kutupa kwa ziwalo

Tayesa zinthu zambiri za granite ndikuyerekeza zinthuzi. Pomaliza tapeza zotsatira zake, granite wakuda wa Jinan ndiye chinthu chabwino kwambiri chomwe tidadziwapo. Granite wakuda waku India ndi granite waku South Africa ndi ofanana ndi Jinan Black Granite, koma mawonekedwe awo enieni ndi ochepa poyerekeza ndi Jinan Black Granite. ZHHIMG ipitiliza kufunafuna zinthu zambiri za granite padziko lonse lapansi ndikuyerekeza mawonekedwe awo enieni.

Kuti mumve zambiri za granite yoyenera ntchito yanu, chonde titumizireni uthenga.info@zhhimg.com.

Opanga osiyanasiyana amagwiritsa ntchito miyezo yosiyanasiyana. Pali miyezo yambiri padziko lonse lapansi.
DIN Standard, ASME B89.3.7-2013 kapena Federal Specification GGG-P-463c (Granite Surface Plates) ndi zina zotero monga maziko a specifications zawo.

Ndipo tikhoza kupanga mbale yowunikira yolondola ya granite malinga ndi zomwe mukufuna. Takulandirani kuti mulumikizane nafe ngati mukufuna kudziwa zambiri zokhudza miyezo yambiri.

Kusalala kungaganizidwe ngati mfundo zonse pamwamba zili mkati mwa magawo awiri ofanana, gawo loyambira ndi gawo la denga. Kuyeza mtunda pakati pa mapepala ndi kusalala konse kwa pamwamba. Kuyeza kumeneku kumakhala ndi kulekerera ndipo kungaphatikizepo chizindikiro cha giredi.

Mwachitsanzo, kulekerera kwa flatness kwa magiredi atatu okhazikika kumafotokozedwa mu statement ya federal monga momwe zakhazikitsidwira ndi formula yotsatirayi:
■ Giredi ya Laboratory AA = (40 + yopingasa sikweya/25) x .000001" (ya mbali imodzi)
■ Kuyang'anira Giredi A = Giredi ya Laboratory AA x 2
■ Chipinda cha Chida Giredi B = Giredi ya Laboratory AA x 4.

Pa ma plates okhazikika a pamwamba, tikutsimikizira kuti ma plates osalala amapitilira zomwe zimafunikira pa izi. Kuphatikiza pa kusalala, ASME B89.3.7-2013 & Federal Specification GGG-P-463c akufotokoza mitu kuphatikizapo: kulondola kobwerezabwereza muyeso, mawonekedwe a granite pamwamba pa plate, kutha kwa pamwamba, malo othandizira, kuuma, njira zovomerezeka zowunikira, kukhazikitsa zoyikapo ulusi, ndi zina zotero.

Ma granite pamwamba pa ZHHIMG ndi ma granite oyang'anira ma granite amakwaniritsa kapena kupitirira zofunikira zonse zomwe zafotokozedwa mu izi. Pakadali pano, palibe mfundo yeniyeni ya ma granite angle plates, parallels, kapena master squares.

Ndipo mungapeze njira zina zogwiritsira ntchito miyezo muTSITSANI.

Choyamba, ndikofunikira kusunga mbaleyo kukhala yoyera. Fumbi loyabwa lochokera mumlengalenga nthawi zambiri limakhala gwero lalikulu la kuwonongeka ndi kung'ambika pa mbale, chifukwa limakonda kulowa m'zigawo zogwirira ntchito ndi malo olumikizirana a gages. Chachiwiri, phimbani mbale yanu kuti muiteteze ku fumbi ndi kuwonongeka. Nthawi yovala ikhoza kukulitsidwa mwa kuphimba mbaleyo pamene sikugwiritsidwa ntchito, mwa kuzunguliza mbaleyo nthawi ndi nthawi kuti malo amodzi asagwiritsidwe ntchito mopitirira muyeso, komanso mwa kusintha ma contact pads achitsulo poyesa ndi ma carbide pads. Komanso, pewani kuyika chakudya kapena zakumwa zoziziritsa kukhosi pa mbaleyo. Dziwani kuti zakumwa zambiri zoziziritsa kukhosi zimakhala ndi carbonic kapena phosphoric acid, zomwe zimatha kusungunula mchere wofewa ndikusiya mabowo ang'onoang'ono pamwamba pake.

Izi zimadalira momwe mbale ikugwiritsidwira ntchito. Ngati n'kotheka, tikukulimbikitsani kuyeretsa mbale kumayambiriro kwa tsiku (kapena nthawi yogwira ntchito) komanso kumapeto. Ngati mbaleyo yadetsedwa, makamaka ndi mafuta kapena madzi omatira, iyenera kutsukidwa nthawi yomweyo.

Tsukani mbale nthawi zonse ndi madzi kapena ZHHIMG Waterless surface plate cleaner. Kusankha njira zotsukira ndikofunikira. Ngati chosungunulira chosasunthika chikugwiritsidwa ntchito (acetone, lacquer thinner, alcohol, ndi zina zotero) nthunzi idzaziziritsa pamwamba pake, ndikuyipotoza. Pankhaniyi, ndikofunikira kulola mbaleyo kuti ibwerere mwakale musanagwiritse ntchito kapena zolakwika zoyezera zingachitike.

Nthawi yomwe imafunika kuti mbaleyo isinthe imasintha malinga ndi kukula kwa mbaleyo, komanso kuchuluka kwa kuzizira. Ola limodzi liyenera kukhala lokwanira mbale zazing'ono. Maola awiri angafunike mbale zazikulu. Ngati chotsukira chogwiritsa ntchito madzi chikugwiritsidwa ntchito, padzakhalanso kuzizira kochokera mu nthunzi.

Mbaleyi imasunganso madzi, ndipo izi zingayambitse dzimbiri pazigawo zachitsulo zikakhudzana ndi pamwamba pake. Otsukira ena amasiyanso zotsalira zomata zikauma, zomwe zimakopa fumbi louluka, ndipo kwenikweni zimawonjezera kuwonongeka, m'malo mochepetsa.

Izi zimadalira momwe mbaleyo imagwiritsidwira ntchito komanso malo omwe ili. Tikukulimbikitsani kuti mbale yatsopano kapena chowonjezera cha granite cholondola chilandire kukonzedwanso kwathunthu mkati mwa chaka chimodzi mutagula. Ngati mbale ya granite pamwamba pake igwiritsidwa ntchito kwambiri, kungakhale koyenera kufupikitsa nthawiyi mpaka miyezi isanu ndi umodzi. Kuyang'ana pamwezi kuti muwone zolakwika zobwerezabwereza pogwiritsa ntchito mulingo wamagetsi, kapena chipangizo chofananacho kudzawonetsa malo aliwonse omwe akuwonongeka ndipo zimatenga mphindi zochepa kuti zichitike. Pambuyo poti zotsatira za kukonzedwanso koyamba zapezeka, nthawi yowerengera ikhoza kukulitsidwa kapena kufupikitsidwa monga momwe dongosolo lanu lamkati limaloleza kapena kufunikira.

Tikhoza kukupatsani chithandizo chokuthandizani kuyang'ana ndikukonza mbale yanu ya granite pamwamba.

Pali zifukwa zingapo zomwe zingayambitse kusiyana pakati pa ma calibration:

• Pamwamba pake panatsukidwa ndi madzi otentha kapena ozizira musanayesedwe, ndipo sanapatsidwe nthawi yokwanira kuti zinthu zisinthe.
• Mbaleyi siithandizidwa bwino
• Kusintha kwa kutentha
• Ma drafti
• Kuwala kwa dzuwa mwachindunji kapena kutentha kwina kowala pamwamba pa mbaleyo. Onetsetsani kuti magetsi a pamwamba sakutenthetsa pamwamba pake.
• Kusintha kwa kutentha koyima pakati pa nyengo yozizira ndi chilimwe (Ngati n'kotheka, dziwani kutentha koyima panthawi yomwe kuyesedwa kumachitika.)
• Mbale siipatsidwa nthawi yokwanira kuti isinthe pambuyo potumiza
• Kugwiritsa ntchito zida zowunikira molakwika kapena kugwiritsa ntchito zida zosagwiritsidwa ntchito
• Kusintha kwa pamwamba chifukwa cha kuvala

Kodi ndi mitundu ingati ya mabowo pa granite yolondola?

Mipata pa Zigawo za Granite Yoyenera

Kwa mafakitale ambiri, zipinda zowunikira ndi ma laboratories, ma granite pamwamba pa nthaka olondola amagwiritsidwa ntchito ngati maziko a muyeso wolondola. Chifukwa muyeso uliwonse wolunjika umadalira malo olondola omwe miyeso yomaliza imatengedwa, ma plate pamwamba amapereka malo abwino kwambiri owunikira ntchito ndi kapangidwe kake asanayambe kupangidwa. Ndi maziko abwino kwambiri opangira miyeso ya kutalika ndi malo owunikira. Kuphatikiza apo, kusalala kwambiri, kukhazikika, khalidwe lonse komanso luso lapamwamba zimapangitsa kuti zikhale chisankho chabwino chokhazikitsa makina apamwamba, zamagetsi komanso owunikira. Pa njira iliyonse yoyezera iyi, ndikofunikira kusunga ma plate pamwamba pa nthaka ali olondola.

Repeat Measurements and Flatness

Kuyeza kwa kusalala ndi kubwerezabwereza ndikofunikira kwambiri kuti malo awoneke bwino. Kusalala kumatha kuonedwa ngati mfundo zonse pamwamba zili mkati mwa magawo awiri ofanana, gawo loyambira ndi gawo la denga. Kuyeza mtunda pakati pa mapepala ndi kusalala konse kwa pamwamba. Kuyeza kwa kusalala kumeneku nthawi zambiri kumakhala ndi kulekerera ndipo kungaphatikizepo chizindikiro cha giredi.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

Muyezo wa DIN, Muyezo wa GB, Muyezo wa ASME, Muyezo wa JJS... dziko losiyana ndi malo osiyana...

Zambiri zokhudza muyezo.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Kuti atsimikizire kuti mbale ya pamwamba ikugwirizana ndi kusalala komanso kuyeza kobwerezabwereza, opanga ma granite pamwamba ayenera kugwiritsa ntchito Federal Specification GGG-P-463c ngati maziko a zomwe amafotokoza. Muyezo uwu umafotokoza kulondola kwa kuyeza kobwerezabwereza, mawonekedwe a granite pamwamba pa mbale, kutha kwa pamwamba, malo othandizira, kuuma, njira zovomerezeka zowunikira ndi kukhazikitsa zoyikamo ulusi.

Checking Plate Accuracy

Potsatira malangizo ochepa osavuta, ndalama zomwe zimagwiritsidwa ntchito pa granite pamwamba pa mbale ziyenera kukhala zaka zambiri. Kutengera momwe mbale imagwiritsidwira ntchito, malo ogulitsira komanso kulondola komwe kumafunika, kuchuluka kwa nthawi yowunikira kulondola kwa mbale pamwamba kumasiyana. Lamulo lalikulu ndilakuti mbale yatsopano ilandire kukonzedwanso kwathunthu mkati mwa chaka chimodzi mutagula. Ngati mbaleyo imagwiritsidwa ntchito pafupipafupi, ndibwino kufupikitsa nthawi imeneyi kufika pa miyezi isanu ndi umodzi.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

Nthawi zina, pamakhala kusiyana pakati pa kuyeza kwa pamwamba pa mbale. Nthawi zina zinthu monga kusintha kwa pamwamba chifukwa cha kuwonongeka, kugwiritsa ntchito molakwika zida zowunikira kapena kugwiritsa ntchito zida zosayezedwa zimatha kuyambitsa kusiyana kumeneku. Komabe, zinthu ziwiri zomwe zimafala kwambiri ndi kutentha ndi chithandizo.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Kutsatira malangizo angapo kumachepetsa kuwonongeka kwa mbale ya granite pamwamba pake ndipo pamapeto pake, kukulitsa moyo wake.

Choyamba, ndikofunikira kusunga mbaleyo kukhala yoyera. Fumbi lochokera mumlengalenga nthawi zambiri limakhala gwero lalikulu la kuwonongeka ndi kung'ambika kwa mbaleyo, chifukwa limakonda kulowa m'zida zogwirira ntchito komanso pamalo olumikizirana a ma gauge.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Zungulirani mbale nthawi ndi nthawi kuti malo amodzi asagwiritsidwe ntchito mopitirira muyeso. Komanso, tikukulimbikitsani kuti musinthe ma contact pads achitsulo poyesa ndi ma carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Ngati mbale ya granite pamwamba ikufunika kukonzedwanso, ganizirani ngati ntchito imeneyi ichitike pamalopo kapena pamalo oyezera. Nthawi zonse ndibwino kuti mbaleyo ikonzedwenso ku fakitale kapena pamalo ena apadera. Komabe, ngati mbaleyo sinawonongeke kwambiri, nthawi zambiri mkati mwa mainchesi 0.001 kuchokera pa kulekerera kofunikira, ikhoza kukonzedwanso pamalopo. Ngati mbale yavala mpaka kufika poti yapitirira mainchesi 0.001 kuchokera pa kulekerera kofunikira, kapena ngati yaphwanyika kwambiri kapena yawonongeka, ndiye kuti iyenera kutumizidwa ku fakitale kuti ikaphwanyidwe isanayambikenso.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Muyenera kusamala kwambiri posankha katswiri wokonza ndi kukonzanso malo omwe alipo. Pemphani kuti akupatseni chilolezo ndikutsimikizira kuti zida zomwe katswiriyo angagwiritse ntchito zili ndi njira yowunikira. Chidziwitso nachonso ndi chofunikira, chifukwa zimatenga zaka zambiri kuti muphunzire momwe mungapangire granite molondola.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Pamwamba pake panatsukidwa ndi madzi otentha kapena ozizira musanayesedwe ndipo sanapatsidwe nthawi yokwanira kuti zinthu zisinthe.

2. Mbaleyi siithandizidwa bwino.

3. Kusintha kwa kutentha.

4. Ma drafti.

5. Kuwala kwa dzuwa mwachindunji kapena kutentha kwina kowala pamwamba pa mbaleyo. Onetsetsani kuti magetsi a pamwamba sakutenthetsa pamwamba pake.

6. Kusintha kwa kutentha koyima pakati pa nyengo yozizira ndi chilimwe. Ngati n'kotheka, dziwani kutentha koyima panthawi yomwe kuyesedwa kumachitika.

7. Mbale siipatsidwa nthawi yokwanira kuti isinthe zinthu pambuyo potumiza.

8. Kugwiritsa ntchito molakwika zida zowunikira kapena kugwiritsa ntchito zida zosagwiritsidwa ntchito.

9. Kusintha kwa pamwamba chifukwa cha kuwonongeka.

Tech Tips

• Popeza muyeso uliwonse wa mzere umadalira malo olondola ofotokozera omwe miyeso yomaliza imatengedwa, ma plates apamwamba amapereka malo abwino kwambiri ofotokozera ntchito ndi kapangidwe kake asanayambe kupangidwa.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Pulogalamu yowunikira yogwira mtima iyenera kuphatikizapo kufufuza pafupipafupi ndi autocollimator, kupereka kuwunikira kwenikweni kwa kusalala konse komwe kungatsatidwe ndi National Inspection Authority.

Pakati pa tinthu ta mchere tomwe timapanga granite, opitilira 90% ndi feldspar ndi quartz, omwe feldspar ndiye ambiri. Feldspar nthawi zambiri imakhala yoyera, imvi, komanso yofiira ngati thupi, ndipo quartz nthawi zambiri imakhala yopanda mtundu kapena yoyera ngati imvi, yomwe imapanga mtundu woyambira wa granite. Feldspar ndi quartz ndi mchere wolimba, ndipo zimakhala zovuta kusuntha ndi mpeni wachitsulo. Ponena za mawanga akuda mu granite, makamaka mica yakuda, palinso mchere wina. Ngakhale kuti biotite ndi yofewa, kuthekera kwake kupirira kupsinjika sikofooka, ndipo nthawi yomweyo amakhala ndi granite yochepa, nthawi zambiri osakwana 10%. Uwu ndiye mkhalidwe wazinthu zomwe granite imakhala yolimba kwambiri.

Chifukwa china chomwe granite ilili yolimba ndichakuti tinthu ta mchere timene timakhala tomangirana bwino ndipo timalowa mkati mwa wina ndi mnzake. Ma pores nthawi zambiri amakhala osakwana 1% ya kuchuluka konse kwa miyala. Izi zimapatsa granite mphamvu yopirira kupsinjika kwamphamvu ndipo chinyezi sichilowa mosavuta.

Zigawo za granite zimapangidwa ndi miyala yopanda dzimbiri, kukana asidi ndi alkali, kukana kuvala bwino komanso kukhala ndi moyo wautali, palibe kukonza kwapadera. Zigawo zolondola za granite zimagwiritsidwa ntchito kwambiri popanga zida zamafakitale. Chifukwa chake, zimatchedwa zigawo zolondola za granite kapena zigawo za granite. Makhalidwe a zigawo zolondola za granite ndi ofanana ndi a nsanja za granite. Chiyambi cha zida ndi muyeso wa zigawo zolondola za granite: Kukonza molondola ndi ukadaulo wa micro machining ndi njira zofunika kwambiri zopititsira patsogolo makampani opanga makina, ndipo zakhala chizindikiro chofunikira poyesa mulingo wapamwamba. Kukula kwa ukadaulo wapamwamba ndi makampani oteteza sikusiyana ndi ukadaulo wolondola wa machining ndi micro-machining. Zigawo za granite zimatha kutsetsereka bwino muyeso, popanda kuima. Kuyeza pamwamba pa ntchito, kukanda konsekonse sikukhudza kulondola kwa muyeso. Zigawo za granite ziyenera kupangidwa ndikupangidwa malinga ndi zofunikira za mbali yofunikira.

Munda wofunsira:

Monga tonse tikudziwira, makina ndi zida zambiri zikusankha zigawo za granite zolondola.

Zigawo za granite zimagwiritsidwa ntchito poyendetsa zinthu modabwitsa, ma mota olunjika, cmm, cnc, makina a laser...

Takulandirani kuti mulankhule nafe kuti mudziwe zambiri.

Zipangizo zoyezera granite ndi zida zamakina za granite zimapangidwa ndi granite wakuda wa Jinan wapamwamba kwambiri. Chifukwa cha kulondola kwawo kwakukulu, nthawi yayitali, kukhazikika bwino komanso kukana dzimbiri, zakhala zikugwiritsidwa ntchito kwambiri poyang'ana zinthu zamafakitale amakono komanso madera asayansi monga malo oyendera ndege ndi kafukufuku wasayansi.

Ubwino

-----Kulimba kawiri kuposa chitsulo chosungunuka；

---- Kusintha kochepa kwa kukula kumachitika chifukwa cha kusintha kwa kutentha；

-----Wopanda kupotoza, kotero palibe kusokoneza ntchito；

-----Yopanda ma burrs kapena ma protrusions chifukwa cha kapangidwe kake ka tirigu wabwinobwino komanso kumamatira kosafunikira, komwe kumatsimikizira kuti imakhala yosalala kwambiri pa moyo wautali wautumiki ndipo sikuwononga ziwalo zina kapena zida zina;

-----Ntchito yopanda mavuto yogwiritsidwa ntchito ndi zipangizo zamaginito;

-----Imakhala nthawi yayitali komanso yopanda dzimbiri, zomwe zimapangitsa kuti pakhale ndalama zochepa zokonzera.

Mapepala olondola a granite pamwamba pake amalumikizidwa bwino kwambiri kuti akwaniritse kulondola ndipo amagwiritsidwa ntchito ngati maziko oyika makina apamwamba, zamagetsi, ndi zoyezera kuwala.

Zina mwa zinthu zapadera za granite pamwamba pa mbale:

Kufanana mu Kuuma;

Zolondola pansi pa katundu;

Choletsa Kugwedezeka;

Yosavuta Kuyeretsa;

Wosagwira Mapepala;

Kutsika kwa Porosity;

Osakwirira;

Osati Maginito

Ubwino wa Granite Surface Plate

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

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Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.