Prefer Jinan Green and fine-grained dense diabase granite; prohibit coarse-grained, layered, or cracked materials:
Mohs hardness HS\u226570, wear and scratch resistant;
Water absorption rate \u22640.15%, avoiding deformation due to temperature and humidity-induced water absorption;
Coefficient of linear expansion \u22644.5\u00d710\u207b\u2076\/\u2103, excellent thermal stability;
Free of mica, sulfides, dark cracks, sand holes, and air pores;
High elastic modulus, minimal deflection under compression huishijm.c\u2026<\/li>\n\n\n\n
After rough cutting, the raw block must undergo constant-temperature natural aging for 72~168h to release billion-year-old geological stresses cutting mechanical stresses; high-precision 000\/00 grade plates undergo an additional constant-temperature static rest to prevent long-term slow warping deformation of the finished product Jiancaiwang.<\/li>\n\n\n\n
Petrographic analysis, hardness, water absorption rate, dimensional uniformity, internal ultrasonic flaw detection (to screen for hidden cracks); unqualified raw blocks are scrapped directly.
II. Full-Process Manufacturing Quality Control (Process Precision Convergence)
Complete process chain: Rough cutting \u2192 Rough milling and shaping \u2192 Aging \u2192 Semi-precision grinding \u2192 Precision grinding \u2192 Ultra-precision polishing \u2192 Drilling \/ Slotting \u2192 Full inspection, with mandatory closed-loop inspection for each process.<\/li>\n\n\n\n
Constant temperature, constant humidity, dust-free, and anti-vibration workshop:
Temperature: 20\u2103\u00b10.5\u2103, hourly fluctuation <0.3\u2103;
Humidity: 45%~55% RH, to prevent hygroscopic expansion;
Independent vibration isolation foundation, vibration acceleration <0.01g;
Class 10,000 air cleanliness, to avoid abrasive scratches on the working surface Huagong Yiqiwang.<\/li>\n\n\n\n
Progressive grinding with multi-stage diamond abrasives to gradually converge flatness error:
Rough grinding 80~120 grit: Remove milling tool marks, flatness \u22640.02mm\/m;
Semi-precision grinding 240~400 grit: Ra\u22643.2\u03bcm;
Precision grinding 800~3000 grit: Working surface Ra\u22640.63\u03bcm;
000\/00 grade ultra-polishing: Cerium oxide polishing, Ra\u22640.0<\/li>\n<\/ol>\n\n\n\n
III. Precise Measurement Methods for Key Geometric Accuracy of Finished Products Mandatory Measured Indicators: Surface waviness, side perpendicularity, top and bottom surface parallelism, surface roughness, appearance defects, rated load deflection. Douyin Baike.<\/p>\n\n\n\n (II) Four Mainstream High-Precision Measurement Methods (from low to high accuracy)<\/p>\n\n\n\n (III) Auxiliary Form and Position Accuracy Measurement IV. Factory Finished Product Quality Control and Certification System Precise Measurement and Quality Control of Precision Granite PlatesPrecision granite (granite stone) plates serve as the reference plane for metrology, CMM, optical inspection, and precision assembly. Core control is divided into six major modules: raw material quality control, full-process manufacturing quality control, high-precision finished product measurement, factory verification, in-service periodic calibration, and usage\/maintenance quality control….<\/p>","protected":false},"author":1,"featured_media":3067,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[35],"tags":[],"class_list":["post-3066","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"taxonomy_info":{"category":[{"value":35,"label":"NEWS"}]},"featured_image_src_large":["https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/07\/123.png",500,375,false],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/ar\/author\/jtlcnc\/"},"comment_info":0,"category_info":[{"term_id":35,"name":"NEWS","slug":"news","term_group":0,"term_taxonomy_id":35,"taxonomy":"category","description":"","parent":0,"count":311,"filter":"raw","cat_ID":35,"category_count":311,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts\/3066","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/comments?post=3066"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts\/3066\/revisions"}],"predecessor-version":[{"id":3068,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/posts\/3066\/revisions\/3068"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/media\/3067"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/media?parent=3066"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/categories?post=3066"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/ar\/wp-json\/wp\/v2\/tags?post=3066"}],"curies":[{"name":"\u062f\u0628\u0644\u064a\u0648 \u0628\u064a","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
(I) Core Indicator Tolerance Grading (GB\/T4987, 20\u00b0C Standard Temperature)
Flatness Tolerance Formula: (T=K\u00d7(1 d\/1000) \\ \\mu m), where d is the platform diagonal in mm.<\/p>\n\n\n\nTolerance Grade<\/th> Coefficient K<\/th> 1000mm Diagonal Flatness<\/th> \u0633\u064a\u0646\u0627\u0631\u064a\u0648 \u0627\u0644\u062a\u0637\u0628\u064a\u0642<\/th><\/tr><\/thead> 000 Grade<\/td> 1<\/td> \u22482\u03bcm<\/td> Optical metrology, laser interferometry reference, semiconductors<\/td><\/tr> 00 Grade<\/td> 2<\/td> \u22483\u03bcm<\/td> CMM laboratory, metrology calibration room<\/td><\/tr> 0 Grade<\/td> 4<\/td> \u22486\u03bcm<\/td> Precision molds, aerospace component inspection<\/td><\/tr> 1 Grade<\/td> 8<\/td> \u224812\u03bcm<\/td> Machining workshop routine inspection<\/td><\/tr> 2 Grade<\/td> 16<\/td> \u224824\u03bcm<\/td> Ordinary marking, assembly positioning<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n \n
Tools: Grade 0 granite straightedge, digital dial indicator with 0.1\u03bcm resolution, bridge plate;
Layout: Four sides two diagonals segmented measurement;
Judgment: The maximum gap represents the local flatness error, suitable for workshop initial inspection.<\/li>\n\n\n\n
Equipment: 0.001mm\/m high-precision electronic level, standard bridge plate;
Layout: Cross shape (diagonals central cross) or full 5\u00d75 grid coverage;
Bridge plate end-to-end overlapping segmented scanning, recording tilt angle readings;
Least squares method fitting to ideal reference plane, calculating global flatness error;
Simultaneously outputting surface waviness (local micro-undulations directly affecting workpiece measurement repeatability) xian.shand\u2026<\/li>\n\n\n\n
Optical reference non-contact measurement, eliminating bridge plate self-weight bending error, suitable for large Grade 00 platforms over 2m, continuous segmented collection of tilt data, computer-fitted plane.<\/li>\n\n\n\n
Using laser wavelength as the length reference, interference fringes directly converted to height difference, measurement accuracy up to 0.1\u03bcm, used for traceability verification of the highest-level platforms in metrology institutes.<\/li>\n<\/ol>\n\n\n\n
Perpendicularity: Grade 00 granite square dial indicator, measuring the perpendicularity of the side to the working surface, tolerance \u2264 Grade 12 (GB\/T1184);
Parallelism: Standard reference platform stacking and dial reading, height difference between top and bottom working surfaces;
Surface Roughness: Surface roughness tester, working surface Ra \u2264 0.63\u03bcm;
Coloring and Lapping Inspection (Auxiliary verification): Uniformly apply red lead powder to a standard straightedge, \u226525 lapping spots within a 25\u00d725mm square represent microscopic plane uniformity without local depressions or pits Zhenjiang Thailand\u2026
(IV) Essential Pre-measurement Conditions (To avoid measurement distortion)
Platform constant temperature rest for 24h, completely consistent with ambient temperature;
Working surface free of dust, oil stains, iron filings, and water stains;
Level and bridge plate pre-tempered to constant temperature, eliminating temperature difference of measuring instruments;
Measurement area free of fans, direct sunlight, and machine tool vibrations.<\/p>\n\n\n\n
Full Outgoing Inspection Checklist
Appearance defects (no cracks, sand holes, scratches) \u2192 Dimensional tolerance \u2192 Flatness \u2192 Planarity fluctuation \u2192 Perpendicularity \u2192 Parallelism \u2192 Roughness \u2192 Load deflection test;
Qualification Criteria
All indicators must simultaneously meet the corresponding grade tolerances; any single indicator exceeding the tolerance must be reworked and precision-ground; downgrading and releasing the product is strictly prohibited;
Traceability Certificate
Issue a CNAS traceable verification report, marking the testing environment, instrument model, original flatness data, error distribution chart, and accuracy grade, to be delivered with the platform.
V. In-service Quality Control (Long-term Precision Maintenance)<\/p>\n\n\n\n\n
Class 000\/00 Metrology Lab: Calibrate every 3\u20136 months;
Class 0 Precision Inspection Room: Calibrate annually;
Class 1 Machining Workshop: Calibrate every 1\u20132 years;
Class 2 General Workstation: Calibrate every 2\u20133 years;
Heavy-duty, impact, or oil-contaminated harsh environments shorten the cycle by half hxrtools.c\u2026<\/li>\n\n\n\n
Daily Cleaning: Wipe with waterless alcohol lint-free cloth; wire brushes and hard tools are prohibited for scraping;
Weekly Visual Inspection: Check for bumps, chipped corners, cracks, and obvious scratches;
Monthly Simple Verification: Color-coat standard gauge blocks for lapping to judge if local planarity has deteriorated.<\/li>\n\n\n\n
Keep away from heat sources, welding machines, machine tool vibrations, and direct sunlight from doors and windows;
Equip with three-point vibration-isolating supports; direct placement on the ground is prohibited;
Overloading, single-point heavy impact, and dragging workpieces across the surface are prohibited;
For long-term idle storage, flip the platform every 3 months to offset gravity-induced creep deformation.
VI. Common Quality Defects and Rectification Solutions
\u0627\u0644\u062c\u062f\u0648\u0644
Defect Phenomenon | Root Cause | Quality Control Rectification Measures
Flatness out of tolerance, middle bulging \/ corners lifting | Insufficient aging, large temperature difference during grinding, unreasonable support | Re-perform constant-temperature aging, comprehensive secondary precision grinding, adjust three-point support
Localized dense scratches | Machining dust, workpiece dragging | Polish to repair, standardize the use of protective pads
Sparse lapping spots, local high points | Grinding abrasive particle size jumps, uneven polishing | Gradual fine grinding uniform polishing, local correction via laser interferometry
Slow deformation during long-term use | High water absorption of stone, drastic temperature and humidity fluctuations | Replace with low-absorption stone, install constant-temperature covers at workstations
Perpendicularity out of tolerance | Side machining grinding vibration | Fine grinding of the side, section-by-section correction with a square ruler
VII. Summary: Complete Quality Control Closed-Loop Logic
Raw material screening \u2192 Natural aging for stress relief \u2192 Constant-temperature anti-vibration graded grinding \u2192 Multi-method high-precision measurement of finished products \u2192 Factory verification and traceability \u2192 In-service cycle calibration daily maintenance
The entire system revolves around the core characteristics of granite\u2014low expansion, high stability, and non-magnetic. Through environmental temperature control, stress elimination, micron-level optical measurement, and periodic calibration, it ensures the platform maintains its reference plane precision over the long term, meeting the traceability requirements of precision manufacturing and metrological testing.<\/li>\n<\/ol>\n\n\n\n![\"\"](\"https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/07\/123.png\")
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