How to control the quality of mold outsourcing processing

How to control the quality of mold outsourcing processing
The root cause of outsourcing loss of control is unclear standards and invisible processes. Control relies on three things: outsourcing lists, process records, and re inspection upon arrival.
Which processes are suitable for outsourcing
Heat treatment, coating, five axis precision machining, and three coordinate inspection are common outsourced items.
Heat treatment and coating are special processes, and their quality cannot be fully verified through post inspection, making them the most difficult to control.
Five axis machining and testing belong to the dimension category and can be verified through re inspection, with relatively low risk.
What should be included in the outsourcing list
Each outsourcing should specify: process content, technical standards, acceptance methods, delivery time, and responsibility allocation.
The hardness range, infiltration depth, allowable deformation, and detection method should be clearly stated for heat treatment.
Just writing 'according to the blueprint' is not enough. Drawings often do not include process parameter requirements.
Requirements for process recording
Temperature curves and hardness testing records should be provided for heat treatment. The curve shows whether the insulation time and cooling method comply with the process.
The coating should provide records of film thickness and adhesion testing. If the film thickness deviation exceeds 20%, the effect will significantly decrease.
Xinfeng Mold will require suppliers to provide curves along with the batch for outsourced heat treatment as part of quality traceability.
Re inspection upon arrival
Dimensional outsourced parts shall be rechecked according to the drawings, with a focus on key dimensions and positional tolerances.
Perform hardness sampling on heat-treated parts, with a sampling ratio of no less than 10%. Double the sampling when the hardness is abnormal.
Perform film thickness testing and visual inspection on coated parts. Local holiday coating is the most common problem.
Supplier Evaluation
Outsourced suppliers should possess the corresponding qualifications and equipment. The heat treatment plant should have a furnace temperature uniformity testing report.
Evaluation is not only based on price, but also on delivery stability and abnormal response speed.
Conduct an annual review to eliminate suppliers with continuous quality issues.
risk control
It is recommended to retain two suppliers for key processes to avoid single reliance.
Outsourced parts and self-made products should be distinguishable and labeled to avoid mixing.
Only when problems can be traced back to specific batches and process parameters, can there be a basis for improvement.
The progress of outsourcing is visible
Require the outsourcing party to provide weekly progress and quality data, and not wait until delivery to know about the delay.
Key processes can be arranged for on-site tracking. The cost is not high, but it can avoid batch rework.
Key points of outsourcing contract
Clearly define quality standards, acceptance methods, breach of contract responsibilities, and confidentiality clauses. The heat treatment process parameters are technical secrets and must be agreed upon not to be disclosed.
exception handling
When the outsourced parts are unqualified, isolate them first and then judge them, do not rework directly. Rework will mask the original defects.
The rework plan needs to be confirmed by the technical department and re inspected after rework.
The packaging of outsourced parts should be anti-collision, with the precision side facing upwards to avoid scratches during transportation.
Outsourced parties should report changes in process parameters in advance, and unauthorized adjustments are a common source of quality fluctuations.
Who is responsible for the transportation of outsourced items should be clearly stated in the contract, and the cost of disputes can be high when the responsibility is unclear.
Frequently Asked Questions
Q: Which processes are suitable for outsourcing?
Answer: Heat treatment, coating, five axis machining, three coordinate inspection.
Q: What should be included in the outsourcing list?
Answer: Process content, standards, acceptance methods, delivery time, and responsibilities.
Q: What records are required for heat treatment?
Answer: Temperature curve and hardness testing records.
Q: What is the proportion of re inspection upon arrival?
Answer: The hardness sampling should not be less than 10%, and it should be doubled in case of abnormalities.
Q: How many outsourcing suppliers do you need?
Answer: It is recommended to keep two key processes.
Q: How to prevent mixing of outsourced parts?
Answer: Make distinguishing marks and manage by batch.
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