Maximizing Accuracy: Tips for Quality Control in Metal Stamping Part Manufacturing

To make sure the accuracy of metal stamping parts during the production process, it is necessary to strictly control each step such as mold design and manufacturing, equipment operation and maintain, material selection, production process control and quality inspection together. Here, we would like to share our view and experience as below :

Part 1 : Mold design and manufacturing

Precise design: Use advanced CAD/CAM software for mold design, and making the accurately plan for the structure, working part size and workable tolerance of the stamping mold according to the specification, make the drawing of dimension and accuracy requirements of the stamping parts. Consider various factors in the stamping process, such as material flow, springback, etc., and optimize the mold design plan through simulation analysis.

Manufacturing operation: using the high-precision processing equipment and advanced  technology to do the molds, such as CNC machining centers, EDM, etc., to ensure the processing accuracy of mold parts meet the quality standard. The processing accuracy of key parts is controlled at the micron level, and the surface roughness reaches Ra0.8-Ra1.6μm.

Mold assembly: Strictly follow the assembly process to assemble the mold to ensure the relative position accuracy between the parts. Use high-precision positioning pins, positioning keys and other positioning elements to ensure that the assembly gaps of upper and lower mold bases, punches, and concave molds are uniform. After assembly, comprehensive debugging and mold testing are carried out to promptly discover and adjust problems with the mold.

Part 2 : Selection and maintenance of stamping equipment

Suitable equipment: According to the precision requirements, production batches and material properties of stamping parts, stamping equipment with high precision and good stability should be selected. For high-precision stamping parts, CNC punching machines, precision presses and other equipment can be selected.

Equipment maintenance: Develop a strict equipment maintenance plan and regularly inspect, maintain and repair stamping equipment. Perform precision inspection and adjustment on key components of the equipment such as sliders, guide rails, transmission systems, etc. to ensure that the various performance indicators of the equipment meet the requirements.

Part 3 : Materials Selection

Know the material properties: Select suitable materials according to the specification requirements and precision requirements of stamping parts. The mechanical properties, thickness tolerance, surface need, etc. of the materials should meet the relevant standards and product specification requirements. For high-precision stamping parts, high-precision cold-rolled steel plates, stainless steel plates and other materials are preferred.

Material inspection: Strict check the materials, including dimensional accuracy, mechanical properties, chemical composition and other aspects. Use measuring tools such as calipers and micrometers to measure the thickness, width and other dimensions of the material to make sure  that the dimensional deviation is within the tolerance range.

Part 4 : Production process control

Process formulation: According to the shape, size, precision requirements and material properties of the stamped parts, do a reasonable stamping process plan. Determine the appropriate process parameters such as stamping process, stamping sequence, stamping speed and stamping pressure accordingly.

First sample inspection: Before mass production, the first sample is stamped and a comprehensive inspection is carried out. Mass production can only be carried out after the first piece inspection is qualified. During the production process, random inspections are carried out regularly to promptly discover and deal with stamping part precision problems caused by mold wear, equipment failure and other reasons. 

Environmental control: Keep the production environment clean, dry and temperature stable. Avoid dust, oil and other impurities from entering the stamping die and workpiece surface to affect the stamping accuracy. Control the temperature of the production workshop at 20℃±5℃ and the humidity at 40%-60% to reduce the impact of environmental factors on the precision of stamping parts.

Part 5 : Quality inspection and feedback

Inspection: Using advanced inspection equipment such as 3D measurement machines, optical projectors, profilometers, etc., to conduct the comprehensive inspections on the dimensional accuracy, shape accuracy, and position accuracy of stamping parts. Inspection personnel should have professional inspection knowledge and skills and conduct inspections in strict accordance with inspection standards and operating procedures.

Data Report: Establish a quality data sheet to promptly feedback the inspection results to the production department and the technical department. According to the quality data, analyze the reasons for the excessive precision of stamping parts and take corresponding improvement measures, such as adjusting process parameters, repairing molds, and replacing equipment parts.

Part 6 : Summery

To ensure the accuracy of metal stamping parts in production process, we can start from molds, equipment, materials, processes, testing and other aspects, which are summarized as follows:

6.1 Mold design and making

Reasonably design the mold, using advanced design software for precise modeling and analysis, consider the stamping process and material characteristics, and optimize the structural parameters.

Select high-quality mold materials to ensure good strength, hardness, wear resistance and dimensional stability.

Adopt advanced processing equipment and processes to ensure processing accuracy, perform high-precision milling, EDM, etc., and perform surface treatment after processing.

Maintain the mold regularly, check key components, repair or replace worn parts in time, and do a good job of cleaning and lubrication.

6.2 Equipment

Select stamping equipment with high precision and good stability, and regularly perform precision testing and calibration of the equipment.

Reasonably install and debug the equipment to ensure that the equipment is in good working condition and set appropriate stamping parameters.

6.3 Material

Strictly control the quality of raw materials, check the hardness, strength, thickness uniformity and other indicators of the material.

Pre-treat the material, such as leveling and deburring, to ensure the surface quality and flatness of the material.

6.4 Process control

Develop a scientific and reasonable stamping process plan, conduct process tests and optimization.

Precisely control stamping process parameters, monitor and adjust parameters such as pressure, speed, and stroke.

Adopt advanced stamping process technologies, such as multi-station progressive die stamping, precision stamping, etc.

6.5 : Inspection:

Establish a complete quality inspection system to conduct first-piece inspection, process inspection, and finished product inspection on stamped parts.

Adopt advanced inspection equipment and methods, such as three-coordinate measuring machines, optical projectors, etc., to detect key dimensions and geometric tolerances.

Analyze and feedback the inspection data, and adjust the production process in time.