GB/T 14404-2024 in English

Interpretation of GB/T 14404—2024 "Shearing Machine Accuracy" Standard

I. Background of Standard Revision and Analysis of Technology Evolution

Since its first release in 1993, this standard has undergone several revisions and updates. The main purpose of this revision is to adapt to the development needs of modern shearing machine technology, especially the improvement of numerical control and intelligent trends. Compared with GB/T 14404—2011, the new standard has made important improvements in the following aspects:

• The positioning accuracy and repeat positioning accuracy requirements of the numerical control stop device have been added (see 5.2).
• The uniformity tolerance requirements and inspection methods of the blade edge gap have been optimized.
• More stringent parallelism and flatness inspection standards have been introduced to meet the needs of high-precision shearing.

II. Comparative analysis of standard frameworks

III. In-depth interpretation of core clauses

1. Inspection requirements (4.1)

General requirements specify the following key points:

• The power supply voltage deviation range is controlled within ±10%, and the ambient temperature must be maintained between 5℃ and 40℃.
• Before inspection, the equipment level must be adjusted to ensure that the level reading does not exceed 0.20/1000.
• The inspection exemption clauses for different types of shearing machines are clearly specified (e.g. swing shearing machines are not subject to inspection 4.1.3).

2. Working accuracy test conditions (4.2)

The new standard puts forward higher requirements for the selection and testing methods of test pieces:

• The length of the test piece must comply with the provisions of Table 1 to ensure that the testing range covers the full width of the shearing machine.
• The thickness of the test piece steel plate should be half or close to the thickness of the shearing machine, and the material requirement is Q235-A steel.
• The working accuracy test should be carried out after the full load test (4.2.8).

3. Accuracy requirements and test methods

Geometric accuracy (5.1):

• Uniformity of blade edge gap : New graded tolerance requirements have been added, see Table 2 for details. For example, the maximum allowable deviation value of the gate shearing machine at different shearing widths has been increased.
• Parallelism of lower blade and stopper: The inspection method in GB/T 10923-2009 (5.4.1.2.1) is adopted, and the tolerance levels are divided into Ⅰ, Ⅱ and Ⅲ levels. The specific values are shown in Table 3.

Working accuracy (5.3):

• Test piece straightness: When the tolerance level is Ⅰ, the maximum allowable deviation is 0.20mm over a length of 1000mm. The specific inspection method refers to GB/T 10923-2009 (6.2.1).
• Test piece parallelism: When the tolerance level is Ⅰ, the maximum allowable deviation is 0.15mm over a length of 1000mm. The inspection method adopts multi-point measurement with a vernier caliper (see Figure 6).

IV. Implementation Suggestions

The above implementation suggestions can effectively improve the manufacturing quality and performance of the shearing machine, ensuring its efficient and stable operation in modern industrial production.