English
English
Mold processing is the core link of manufacturing industry, and its quality directly affects product accuracy and production efficiency. The following are key issues that need special attention during the mold processing, covering design, materials, processing technology, and quality control.
1、 Precautions during mold design
1. Reasonably design the mold structure
Ensure a reasonable design of the parting surface for easy demolding
Design sufficient draft angle (usually 1-3 °)
Consider shrinkage rate (usually 0.5-2.5% for plastic molds)
Optimize the layout of the cooling system to ensure uniform cooling
2. Material selection
Select suitable mold steel according to production needs:
Ordinary plastic mold: P20, 718
High wear resistance requirements: H13, S136
High mirror requirement: NAK80
Consider heat treatment performance to avoid subsequent deformation
2、 Preparation before processing
1. Material inspection
Check the hardness and internal defects of the steel (ultrasonic testing)
Confirm that the material size allowance is sufficient (usually leaving 0.3-0.5mm precision machining allowance on one side)
2. Process planning
Develop a reasonable processing technology route:
Text
Rough machining → Semi precision machining → Heat treatment → Precision machining → Electrical machining → Polishing
Determine the machining allowance and tolerance for each process
3、 Key control points in the processing process
1. Precautions for CNC machining
Reasonable selection of cutting tools:
Rough machining: Hard alloy cutting tools
Precision machining: Diamond cutting tools (high hardness materials)
Control cutting parameters:
Speed: Adjust according to material hardness
Feed rate: avoid excessive tool wear
Timely remove chips to prevent secondary cutting
2. Key points of electrical discharge machining (EDM)
Choose suitable electrical materials (copper, graphite)
Control the discharge gap (usually 0.03-0.1mm)
After processing, the white layer (discharge deteriorated layer) needs to be removed
3. Precautions for wire cutting
Maintain appropriate silk tension
Control processing speed to avoid wire breakage
After processing, deburring is required
4、 Heat treatment process control
1. Preparation before heat treatment
Stress relief annealing is required after rough machining
Reserve sufficient machining allowance (may deform by 0.1-0.3mm after heat treatment)
2. Common heat treatment processes
Quenching: Improve hardness (HRC48-52)
Tempering: Eliminating internal stress
Nitriding treatment: Improve surface hardness (HV1000 or above)
5、 Surface treatment and polishing
1. Polishing process
Use oil stones of different particle sizes in order (# 400 → # 800 → # 1200 → # 1500)
Mirror polishing requires the use of diamond grinding paste
Pay attention to maintaining clear edges and avoid over throwing
2. Surface strengthening treatment
TD treatment (improving wear resistance)
PVD coating (TiN, TiCN, etc.)
6、 Assembly and trial molding
1. Key points of mold assembly
Check the coordination accuracy of each component
Ensure smooth movement of the ejection system
Test the sealing performance of the cooling system
2. Precautions for mold testing
Key dimensions for first article inspection
Adjust injection parameters (pressure, temperature, time)
Record trial mold issues and make timely corrections
7、 Common problems and solutions
Possible causes and solutions for the problem phenomenon
Product size deviation, mold deformation/machining error correction, cavity/core size
Insufficient adhesive polishing/small draft angle increases polishing/corrects draft angle
Poor fit of flying edge parting surface and joint parting surface
Difficulty in pushing out the top needle and correcting the top needle hole due to excessive tightness
8、 Mold maintenance and upkeep
Regularly check the lubrication of guiding components
Clean the mold cavity promptly after use
Long term storage requires rust prevention treatment
Establish a mold usage file and record maintenance history
9、 Safety precautions
Wear protective goggles during processing
Heavy duty mold handling using lifting equipment
Pay attention to fire prevention during electrical processing
Heat treatment operations must comply with safety regulations
By strictly controlling the above links, the quality of mold processing can be ensured, the service life of molds can be extended, and production efficiency can be improved. Suggest establishing a comprehensive quality control system and conducting strict inspections on each processing step.
