{"id":3256,"date":"2026-08-14T09:20:11","date_gmt":"2026-08-14T01:20:11","guid":{"rendered":"https:\/\/jtlcnc.com\/?p=3256"},"modified":"2026-08-14T09:20:13","modified_gmt":"2026-08-14T01:20:13","slug":"what-are-the-acceptance-standards-for-granite-platforms","status":"publish","type":"post","link":"https:\/\/jtlcnc.com\/es\/2026\/08\/14\/what-are-the-acceptance-standards-for-granite-platforms\/","title":{"rendered":"What are the acceptance standards for granite platforms?"},"content":{"rendered":"

Complete Acceptance Standards for 00\/000 Grade High-Precision Granite Surface Plates<\/h1>\n\n\n\n

I. Basis of Execution<\/h2>\n\n\n\n
    \n
  1. Domestic National Standard: GB\/T 20428-2006 “Rock Surface Plates”<\/strong> (equivalent to ISO 8512-2:1990) Chinese standard in\u2026<\/li>\n\n\n\n
  2. Metrological Verification Procedure: JJG 117-2013 “Verification Procedure for Surface Plates”<\/strong> (mandatory basis for issuing metrological certificates)<\/li>\n\n\n\n
  3. Mandatory Acceptance Environment Conditions: Constant temperature 20\u00b11\u2103, temperature change rate \u22640.5\u2103\/h, dust-free and vibration-dampened workshop; the plate must be placed in a constant temperature environment for 24 hours for thermal equilibrium before testing.<\/li>\n<\/ol>\n\n\n\n

    II. Part One: Raw Material Acceptance (Mandatory inspection upon arrival, determining long-term deformation resistance)<\/h2>\n\n\n\n

    1. Hard Requirements for Stone Types<\/h3>\n\n\n\n

    Only Jinan Qinghui Longyan \/ Indian Black Fine-grained Granite<\/strong> are permitted; dyed stones, stratified miscellaneous stones, and porous ordinary marble are prohibited.<\/p>\n\n\n\n

    2. Physical Performance Acceptance Indicators<\/h3>\n\n\n\n

    Cuadro<\/p>\n\n\n\n

    Test Item<\/th>00\/000 Grade Qualification Standard<\/th><\/tr><\/thead>
    Densidad<\/td>\u22652.97 g\/cm\u00b3<\/td><\/tr>
    Shore Hardness<\/td>HS\u226572<\/td><\/tr>
    Compressive Strength<\/td>\u2265245 MPa<\/td><\/tr>
    Coeficiente de dilataci\u00f3n lineal<\/td>\u22644.6\u00d710\u207b\u2076\/\u2103<\/td><\/tr>
    Water Absorption Rate<\/td>\u22640.13%<\/td><\/tr>
    Magnetismo<\/td>Completely non-magnetic, does not attract iron filings<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    3. Non-destructive Internal Defect Acceptance<\/h3>\n\n\n\n
      \n
    • Ultrasonic Flaw Detection: No internal dark cracks, inclusions, soft mica bands, or dense sand holes;<\/li>\n\n\n\n
    • Visual Full Inspection: No white spots, loose pores, or delaminated textures;<\/li>\n\n\n\n
    • Aging Certification: Natural aging of raw blocks for 3~6 months complete secondary constant temperature aging records for finished products.<\/li>\n<\/ul>\n\n\n\n

      III. Part Two: Appearance and Surface Quality Acceptance<\/h2>\n\n\n\n
        \n
      1. Working Surface<\/strong><\/li>\n<\/ol>\n\n\n\n
          \n
        • Roughness: Grade 00 Ra\u22640.4\u03bcm; Grade 000 Ra\u22640.1\u03bcm mirror-polished;<\/li>\n\n\n\n
        • No scratches, dents, pits, corrosion spots, or grinding marks; minor scratch depth must not exceed 0.2\u03bcm;<\/li>\n<\/ul>\n\n\n\n
            \n
          1. Edges and Corners<\/strong>
            Full circumference R3~R5 radius chamfering, no chipped edges, broken corners, or sharp edges;<\/li>\n\n\n\n
          2. Sides \/ Bottom Surface<\/strong>
            Flat and burr-free, no obvious coarse saw marks;<\/li>\n\n\n\n
          3. Functional Holes \/ Slots (T-slots, threaded holes)<\/strong>
            Smooth hole walls without cracking; threaded holes must have embedded stainless steel threaded inserts with radius transitions at the hole openings; no stress cracks.<\/li>\n<\/ol>\n\n\n\n

            IV. Part Three: Core Geometric Accuracy Acceptance (Key to the whole unit, detected by laser interferometer)<\/h2>\n\n\n\n

            1. Working Surface Flatness (Core Indicator)<\/h3>\n\n\n\n

            Calculation Formula: Flatness tolerance T=K\u00d7(1 d\/1000) \u03bcm, d = plate diagonal (mm)<\/p>\n\n\n\n

              \n
            • Grade 000: K=1; Flatness of a 1000mm diagonal plate \u22642\u03bcm<\/li>\n\n\n\n
            • Grade 00: K=2; Flatness of a 1000mm diagonal plate \u22643\u03bcm
              Detection Method: Grid multi-point data collection, minimum area method evaluation, laser interferometer \/ autocollimator traceable detection.<\/li>\n<\/ul>\n\n\n\n

              2. Parallelism (Working Surface \u2194 Bottom Surface)<\/h3>\n\n\n\n

              Parallelism tolerance of the top and bottom surfaces is the same as the flatness standard of the corresponding grade, with multi-point differences across the full thickness not exceeding the limit.<\/p>\n\n\n\n

              3. Perpendicularity (Working Surface and Four Side Surfaces)<\/h3>\n\n\n\n

              Grade 00\/000: \u22640.002mm\/m, uniform perpendicularity at the four corners without local tilting.<\/p>\n\n\n\n

              4. External Dimension Tolerances<\/h3>\n\n\n\n

              Length and width: \u00b10.5mm; Thickness: \u00b11.0mm; Diagonal length difference \u22640.003mm\/m.<\/p>\n\n\n\n

              V. Part 4: Load Rigidity \/ Compression Deformation Acceptance (Full Load Deflection Test)<\/h2>\n\n\n\n
                \n
              1. Support Method: Standard three-point support (support points at 20% of length and width from the edges); two-point or single-side support is prohibited;<\/li>\n\n\n\n
              2. Test Procedure: Apply rated uniformly distributed load (conventional 3~5t) at the center of the table, and let it stand for 24h;<\/li>\n\n\n\n
              3. Acceptance Criteria:<\/li>\n<\/ol>\n\n\n\n
                  \n
                • Maximum deflection under load \u2264 1\u03bcm\/200N;<\/li>\n\n\n\n
                • Flatness recovery rate after unloading \u2265 99.98%, no permanent indentation or warping deformation<\/strong>;<\/li>\n<\/ul>\n\n\n\n
                    \n
                  1. Acceptance Purpose: To verify high compression resistance and no plastic deformation under full load.<\/li>\n<\/ol>\n\n\n\n

                    VI. Part 5: Stability Aging Acceptance (Distinguishing between Ordinary Grade 0 and High-Precision Grade 00\/000)<\/h2>\n\n\n\n
                      \n
                    1. Pre-shipment Constant Temperature Static Aging Records:<\/li>\n<\/ol>\n\n\n\n
                        \n
                      • Grade 00: Constant temperature of 20\u2103 for \u2265 14 days;<\/li>\n\n\n\n
                      • Grade 000: Constant temperature for \u2265 28 days, \u2265 90 days for large-sized platforms;<\/li>\n<\/ul>\n\n\n\n
                          \n
                        1. Comparison of Flatness Re-testing Before and After Aging: Difference between the two tests \u2264 0.3\u03bcm\/m, no stress release drift;<\/li>\n\n\n\n
                        2. Vibration Aging Record: 60min vibration stress relief for the finished product to eliminate grinding residual stress.<\/li>\n<\/ol>\n\n\n\n

                          VII. Part 6: Accessories and Documentation Acceptance (Essential for Foreign Trade \/ Metrological Acceptance)<\/h2>\n\n\n\n
                            \n
                          1. Matching Brackets: Three-point adjustable granite vibration-damping brackets, with support points matching the standard support points of the platform;<\/li>\n\n\n\n
                          2. Official Verification Documents: JJG117 Flat Plate Verification Certificate<\/strong> issued by a provincial metrology institute, accompanied by original laser flatness test data, with accuracy traceable to national metrology standards;<\/li>\n\n\n\n
                          3. Material Physical Property Report: Test reports for stone density, hardness, and coefficient of thermal expansion;<\/li>\n\n\n\n
                          4. Process Data: Complete processing and aging records, grinding process records;<\/li>\n\n\n\n
                          5. Protective Packaging: Specialized stone penetration sealing wax, anti-vibration wooden crates, and moisture-proof protective film.<\/li>\n<\/ol>\n\n\n\n

                            VIII. Rejection Items for Non-compliance (Direct rejection if any of the following occur)<\/h2>\n\n\n\n
                              \n
                            1. Stone contains hidden cracks, soft inclusions, or large-area sand holes;<\/li>\n\n\n\n
                            2. Flatness exceeds the tolerance of the corresponding grade;<\/li>\n\n\n\n
                            3. Permanent deformation occurs after unloading from the load test;<\/li>\n\n\n\n
                            4. No formal metrological verification certificate, and accuracy is untraceable;<\/li>\n\n\n\n
                            5. Large-area chipping on edges and corners, or dense deep scratches on the working surface;<\/li>\n\n\n\n
                            6. Incomplete aging treatment, with re-test accuracy drift exceeding the limit;<\/li>\n\n\n\n
                            7. Unauthorized thickness reduction of thin plates, with self-weight bending deflection exceeding the limit.<\/li>\n<\/ol>\n\n\n\n
                              \"\"<\/figure>","protected":false},"excerpt":{"rendered":"

                              Complete Acceptance Standards for 00\/000 Grade High-Precision Granite Surface Plates I. Basis of Execution II. Part One: Raw Material Acceptance (Mandatory inspection upon arrival, determining long-term deformation resistance) 1. Hard Requirements for Stone Types Only Jinan Qinghui Longyan \/ Indian Black Fine-grained Granite are permitted; dyed stones, stratified miscellaneous stones, and porous ordinary marble are…<\/p>","protected":false},"author":1,"featured_media":3258,"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-3256","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\/08\/az-1024x537.png",1024,537,true],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/es\/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":334,"filter":"raw","cat_ID":35,"category_count":334,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts\/3256","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/comments?post=3256"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts\/3256\/revisions"}],"predecessor-version":[{"id":3259,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts\/3256\/revisions\/3259"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/media\/3258"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/media?parent=3256"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/categories?post=3256"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/tags?post=3256"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}