CNC Knowledge: An essential inspection – first article inspection, why is it so important?

In the design and production process of any product, activities such as design changes, process changes, process adjustments, unplanned line stops, production changes and line changes often occur. So how can we ensure that these activities will not affect the quality of subsequent production? This requires first article inspection during the job preparation verification and post-production shutdown verification phases.

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Definition of first article and first article inspection

process change

During the production process, one or more production factors in 5M1E (people, machines, materials, methods, environment and measurement) change, such as personnel changes, equipment adjustments and maintenance, material changes and of accessories, design changes and the stop line. etc.

first article

The first or first products processed on the production line at the start of each shift/production line or after a process change. For mass production, “first item” often refers to a certain number of samples.

first article inspection

Inspection of first or first processed products on the production line at the start of each shift or after a process changeover. The number of inspections can be determined according to the requirements of different companies or customers. Generally speaking, at least 3 to 5 products in continuous production should be inspected. Only after their qualification can the following products be processed. A strict first article inspection is performed before changes are made to equipment or manufacturing processes and before processing begins on each shift.

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The purpose of first article inspection

The main purpose of first article inspection during the production process is to prevent product batches from being out of tolerance, repaired and scrapped. It is a means of prior control of the product production process, an important method of quality control of the product process and a means of prior control. important way for companies to guarantee product quality. An effective and essential method for improving economic efficiency.

First article inspection is to discover the factors that affect product quality in the production process as early as possible and prevent batch defects or scrapping; official production can only start after passing the inspection of the first item, mainly to prevent the emergence of unqualified batch products;

Long-term practical experience has proven that the first inspection system is an effective measure to detect problems as early as possible and prevent products from being scrapped in batches. Through the inspection of the first part, systemic reasons such as significant wear of tool fixtures or installation and positioning errors, deterioration of the accuracy of measuring instruments, incorrect reading of drawings, errors in feeding materials or formulas, etc. can be discovered, so that corrective or improvement measures can be discovered. can be taken to avoid batch failures. The product appears.

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Timing/Occasion of First Article Inspection

Start of each shift

Change operator

Replace or adjust processing equipment and equipment (including replacing or sharpening tools)

Changes in technical conditions, processing methods and process parameters (such as changes in roughness requirements, changes in internal hole bore to bore, changes in tool feed amount or rotation speed in the CNC program, etc.)

After using new materials or material substitution (such as material changes during processing, etc.)

Replace or retest reservoir fluid, etc. (like phosphating, nitriding, etc.)

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First Article Inspection Requirements

First article inspection adopts three inspection system: self-inspection, mutual inspection and special inspection

Products subject to inspection must first be “self-inspected” by the operator, then “mutually inspected” by the team leader or colleagues, and finally “specially inspected” by the inspector. Only the following products may be processed after being determined to be qualified. .

The full-time inspection staff must finally recognize whether the first product is qualified after the inspection. The inspector must mark the first product that passes inspection with the prescribed mark and retain it until the class or batch of products is processed (all first). products should be Retain the sample for later product comparison to see if the process has changed and mark “√” with a marker to indicate successful first item inspection).

If the first item fails inspection, the cause must be identified, action must be taken and the defect must be eliminated before reprocessing and three inspections must be carried out. Only when it passes inspection can it be designated as first article. .

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Main elements of first article inspection

1. Does the drawing number match the work order?

2. Whether the materials, blanks or semi-finished products match the work orders

3. Are the materials, blank surface treatment and installation positioning consistent?

4. Whether the formula ingredients meet the specified requirements

5. Whether the actual quality characteristics of the first product after processing meet the requirements specified in the drawings or technical documents

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First Article Inspection Specification Process

Subject content and scope

This document stipulates the company’s requirements and working procedures for first article inspection and first article inspection of new products during the production process.

This regulation applies to the enterprise’s control over first article inspection and first article inspection of new products during the production process.

Responsibilities

The production department is responsible for arranging and organizing the first item inspection work.

The person directly responsible for any quality accident caused by unauthorized production of products without first-piece inspection of new products, batch first-piece inspection or unqualified first-piece inspection will be held responsible.

The inspector and production line manager are responsible for the accuracy of the first article inspection.

If the first item confirmation work is not completed and the inspector starts to issue a quality certificate, the inspector will be responsible for any quality accidents caused.

control requirements

The first semi-finished products and finished products continuously produced by the production department for the first time must undergo first-piece inspection and confirmation.

For regular production products, first article inspection should be carried out batch by batch.

If the machine is stopped due to equipment, process, etc., initial inspection and confirmation should be carried out when the machine is stopped and restarted.

When materials and product specifications are changed and put into production, first article inspection and confirmation are required.

When the first item of a new product is inspected, the production unit will be responsible for notifying the relevant inspection personnel and proceeding in accordance with the drawings, lists (or samples provided by the customer) and process documents currently in place. force. The inspector must complete. in the inspection file. After passing the inspection, it should be printed on the first article card. Sign and hang the card on the first product to mark the first product. If the first product fails inspection, it must be returned immediately. the first product must be remade and records must be kept. Products that have not passed first article inspection will not be accepted.

The first part is a mass-produced sample and is held by the production department until the entire production batch is completed before it can finally be delivered.

During the first article inspection, all raw and auxiliary materials used in the product production process must be inspected and must comply with regulations.

Working procedures

When producing the first item, the production line manager and inspection personnel should go to the production site to supervise and inspect the actual producers who complete the first item by themselves according to the production process and current and effective standards. documents the production process, and supervise and inspect each production process if problems are found to be corrected and resolved promptly.

The first piece of regular production products and the products produced after stopping and restarting must complete all production processes. Once the producer passes the inspection and signs the first part plate, it will be handed over to the inspector for inspection of the first part.

When inspecting the first part, the inspector should work with the person in charge of the production line to inspect in accordance with the drawings, lists (or samples provided by the customer), process documents and product requirements currently in force. , the first item product must be marked (such as the signature “First Qualified Article”, etc.), and the first article card will be countersigned by the producer (or his representative) and inspection personnel.

First article inspection required due to major changes in the product may be approved by relevant personnel and inspection signature; if the first item fails inspection, it will be immediately returned and the first item will be remade.

The production of the first batch of new products, semi-finished products and finished products generated after changes in materials and specifications requires first-part inspection and confirmation.

When inspecting the first item, the first item registration must be completed on time and the first item confirmation form must be completed.

When quality problems are discovered during the production of the first item, they should be reported and dealt with promptly, and unqualified items should be reconfirmed. Only when the first item passes inspection, the results are recorded on the first item sheet and the quality is recognized by the inspector, can production be arranged.

Only after confirming the first part can the inspector start normal delivery inspection.