Automotive parts are the foundation of the automotive industry and are the elements that support the sustainable and healthy development of the automotive industry. Only strict control can ensure the quality of the final product. In the process of automobile production, batch inspection of workpieces is necessary, but the general manual measurement method is a tedious process that requires constant adjustment of the placement of parts, as well as height measurement that involves measuring the height of different positions one by one, which is time-consuming and inefficient.

In the second stage of APQP, the full-scale measurement of the prototype sample is carried out, and the product design is verified through product testing. In the third stage of APQP, the full-scale measurement of the OTS sample is used to verify the mold and tooling capabilities. During the production of the fourth stage of APQP, it is used to verify whether the qualified products can be stably produced under the take production conditions.

IATF16949 Standard Requirements For Full-Scale Inspection

In clause 8.6.2 full-scale inspection and functional test of the IATF16949 standard, the full-scale measurement and functional verification of all the dimensions shown on the drawings are carried out in the control plan, and submitted to the customer for review.

Fully automatic, high efficiency, can quickly measure the length, width, distance, hole position, curvature and other dimensions of automotive parts.

Introduction To Full-Scale Inspection

What is full size is all the dimensions shown on the drawing. After the full-scale measurement of the prototype sample, the test is carried out for design verification, the full-scale measurement of the OTS sample is used to check the mold and tooling, the full-scale measurement of the beat-produced sample is used to release the PPAP, and the regular inspection of the mass production Full-scale measurement of the sample to verify whether the production status is maintained.


In the second stage of APQP, when the prototype is manufactured, full-scale measurement is carried out;

In the third stage of APQP, full-scale measurement is carried out when OTS prototype is manufactured;

In the fourth stage of APQP, full-scale measurement is carried out during the beat production of trial production.

In the mass production stage, full-scale measurements are carried out at regular intervals according to the control plan.

Input for full size measurements:

1. Drawings, BOM, technical specifications

2. Prototype sample, OTS sample, trial production PPAP sample

3. Sample control plan

4. Mass production control plan

5. Sample measurement plan

Output of full size measurements:

1. Full-scale measurement report

2. Mold tooling rectification plan and plan

Content Of Full Dimensional Measurement

In the APQP Phase II product development and verification stage, a prototype control plan is produced, prototype parts are processed using informal mass production methods, and prototype parts are dimensionally measured and functionally tested to verify that the technical solution of the detailed product design, the selection of product materials, and the tolerance selection of product characteristics meet the final product function and performance requirements. See a previous article, “Why is a prototype used for physical verification of product design?

In the third stage of APQP process development and verification stage, the OTS prototype is a sample part produced under the conditions of formal batch production equipment, tooling, tooling, and process parameters, and then verified layer by layer from materials, parts, systems and the whole machine to verify that the production equipment, tooling, and process parameters can produce the ability to meet the product, thus completing the process design. For details, see a previous article, “Why do we need to test OTS samples?

In the fourth phase of APQP, product and process verification, the pilot production is conducted at the specified production rate to verify the ability to consistently produce products that meet requirements through full-scale measurements of PPAP prototypes.

During the APQP Phase V mass production stage, full dimensional measurements are performed on products in mass production according to the frequency specified in the control plan to verify the ability of the tooling tooling to consistently maintain condition.

Before measuring the sample parts, it is better to make a good measurement plan, including the measurement dimensions, tolerances, nominal values, positions, measurement method tools, etc.

  • 1 – All dimensional markings on the drawing should be numbered and marked.
  • 2 – For multiple identical dimension markings, such as 5*p10±0.2, they should be marked one by one by distinguishing the differences in position and so on.
  • 3 – for the position degree or shape tolerance related dimensions, as far as possible should be put together, to facilitate the data collation and verification after measurement.
  • 4 – All the dimensions in the measurement list must be marked with tolerance requirements, including unannotated tolerances, but also to make up the tolerance.
  • 5 – the drawings in the notes column and size, appearance-related signs do not miss, such as: wall thickness, color, etc.. Wall thickness should generally be multi-point measurement, according to the different parts, some wall thickness also need to determine the location of the measurement point or cutting position.
  • 6 – pay attention to the entire dimensional chain, pay attention to confirm the supplier’s measurement process. Such as the measurement method
  • 7 – Measurement mark drawings must be consistent with the engineering change level of the drawings, such as prototype sample parts are A version of the drawings, OTS sample parts are B version of the drawings, PPAP sample parts are C version of the drawings.

Measurements are performed according to the sample measurement plan, and a measurement report is generated with the following notes.

Measure according to the sample measurement plan, generate a measurement report, the following precautions:

  • 1. At least 3 parts from the PPAP production are taken for full size measurement.
  • 2. For parts from each production process, such as: more than one assembly line and/or workstation, each cavity of a multi-cavity mold, molding die, tooling or model, a minimum of 3 pieces must be taken from each part of the PPAP product for full dimensional measurement. For example, if a mold has three cavities, then each cavity must be measured to, that is, 3*2=6 pieces.
  • 3. Measure according to the requirements of the measurement plan, and the measurement records should correspond to the measurement plan -. As far as possible, the data is measurement data, try to avoid the use of “OK” or “qualified” and other general expressions, in the measurement tool is generally used to distinguish high, universal measurement type.
  • 4. For each ─ item measurement results must be qualified to determine whether.
  • 5. for the test results of the excess, should be marked significantly, the engineer to assess the excess part, to determine whether the need to develop and implement the corresponding corrective measures.
  • 6. The dimensional report must accurately record the design record change level and engineering change documents (if any).
  • 7. The dimensional report must be signed by the engineer.
  • 8. For some complex parts of the CMM report, the original CMM report should be attached.

Reported Results For CMM Inspection Products

The following example demonstrates an appropriate method for reporting inspection results for CMM-inspected parts. A view should be given indicating where the data points of the inspection are located to confirm compliance with the dimensions cited. If a view is not available, a product schematic of the part should be used to show it. The inspection results should indicate each of the cited dimensions that exceed the specifications. For example, the border line strip checks out as low as 0.845 to 1.147.

The CMM print result data point or data check form must refer to the drawing/product schematic and indicate the data point used to confirm the match to the referenced problematic dimension. For example, reference points 31 -34. An additional mark (check mark) should be made on the drawing/product schematic immediately below the reference point when the results meet the specifications.

The following part product schematic is used as an appropriate method of reporting inspection results for surfaces, edges and holes, and does not represent a complete dimensional inspection report. The example for this report is from GM’s GP-11.

In summary, in APQP stage 2, full-dimensional measurements are performed on prototype samples and product testing is used to verify product design, in APQP stage 3, full-dimensional measurements are performed on OTS samples and are used to verify tooling and tooling capabilities, and in APQP stage 4 beat production, they are used to verify that a qualified product can be produced consistently under beat production conditions. In the fifth stage of APQP, full dimensional measurements are performed on the products in mass production according to the frequency specified in the control plan to verify the ability of the tooling and tooling to maintain the status.