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1. Introduction to GR&R
Technical standards are the "technical laws" of the technology and business circles, and they must have three characteristics: normative, objective, unilateral, and relevance. For each performance test, the recognized method for evaluating the performance of the test system is called GR&R (Gauge Repeatability and Reproducibility). This method can determine the ability of a detection system to continuously repeat the same test process, thereby obtaining the reliability index of the detection system. When the measurement uncertainty of a testing system (6 times the GR&R error) does not exceed 25% of the tested product specification range, the testing system has standard norms.
2. The objective independence of the detection system
As far as smt placement equipment is concerned, the most important thing is to quickly and accurately place the components on the PCB pads printed with solder paste, that is, the speed and accuracy indicators. Since the speed and accuracy of the equipment are related to many factors such as component shape, component recognizability,
PCB material performance and manufacturing level, solder paste placement characteristics and printing quality, and the characteristics of the placement machine itself, the errors caused by the equipment must be Separated from the placement process factors. The ideal method is to reduce other factors that may cause patch errors during smt patch proofing or processing. This is the objective independence of the detection system.
3. Minimum parameter set
The performance parameters of the placement machine include: placement speed (yield), variable parameters (measured value), accuracy (also known as accuracy), repeatability (also known as repeatability), reliability, maintainability and applicability, etc. Some of these parameters are related to each other. Only by selecting the minimum parameter set for testing to objectively reflect the actual performance of the equipment, while avoiding the coupling effect between the parameters, can it be solved while simplifying the evaluation process. Relevance issues.
Strategies for handling sluggish materials in PCBA contract labor and material companies
1. Sluggish materials caused by process changes and design changes
The original device is updated very quickly, this is because of the development of science and technology, it may also be the change of the market and the change of policy. The product department makes changes to the company's products due to process or customer needs. The "Engineering Change Notice" must be filled in when the change is made, and PMC will confirm whether the material is in stock or in transit. After receiving the "Engineering Change Notice", PCBA will notify the relevant suppliers as soon as possible to stop the production of such materials. At the same time, PMC organized the product department, production department, sales department, and material department to convene a meeting before filling in the "Dull Material Handling List" to formulate measures to deal with sluggish materials. For the dull materials in stock after the engineering change, the editor of Zhongyan Electronics suggests that they should be modified or replaced in future development or production as much as possible.
2. Sluggish materials caused by inaccurate forecasts or order changes
At present, the market is ever-changing, and many PCBA contract labor and material manufacturing companies are order-oriented production methods, and their plans cannot keep up with the changes in customer needs. When a customer changes or cancels an order, the sales department should notify the material department and the production department as soon as possible. The material and production department will count the quantity of sluggish materials, including inventory quantity, in-process quantity, in-transit quantity, and outsourced processing. quantity. The sales department should communicate with customers as soon as possible based on the cost of materials calculated and be responsible for recovering customer indemnities. PMC cancels the order and issues a return notice. The production department completes the return. The warehouse fills in the "Dull Material Handling List" and sends it to the vice president of production or general manager for handling opinions. Based on this opinion, the warehouse is responsible for temporary storage or scrapping.
If it is due to the sales staff’s inaccurate forecasts, the company has ordered more or wrongly ordered some materials and caused sluggishness, the forecasting method should be improved. The rolling plan method uses the principle of "near fine and far rough" and regularly revises the plan. It is a good method, but it is not a panacea. The focus is to predict market demand based on the customer’s historical sales data, operating capabilities, inventory status, and market changes. For this reason, the account manager should strengthen the analysis of the customer’s order progress, and timely communicate and supervise. And guidance to ensure that customers can place orders in accordance with the forecasted quantity and improve the order fulfillment rate and forecast accuracy rate. In addition, the company’s marketing strategy and daily inventory should promptly inform the account manager to ensure that the account manager’s blindness when collecting market demand orders, actively carry out market demand forecasting, constantly adjust the planning contract, and gradually move the planning method closer to the market method. The forecasted market demand is closer to the actual demand.
