Autor: Martin Dudek Date: October 2014
Česká verze článku ZDE.
The process of approval of parts to series-line production on the basis of the presented documentation provided together with the first trial part/s is called by the abbreviation PPAP (Production Part Approval Process). Until recently, this method has been used mainly in automotive industry and has been (and still is) a part of the APQP process (Advanced Product Quality Planning).
These days it is possible to come across the PPAP also in other branches, not only for serial-made parts. Quite currently, this method has been used by producers of construction machinery, agricultural machinery, rail vehicles, etc.
The result of the PPAP is a set of documents presented to the customer with the first part (s), on the basis of which the customer allows the part to the series-line production.
If we start with requirements of automotive industry based on the fourth edition of the PPAP manual published in 2006 by the group of American automotive factories (Ford, General Motors, Daimler Chrysler), it has got 18 items in total in its list of requirements:
|2.||Authorized Engineering Change Documents|
|3.||Customer Engineering Approval|
|5.||Process Flow Diagram|
|8.||Measurement System Analysis Studies (MSA)|
|10.||Records of Material / Performance Tests|
|11.||Initial Process Studies|
|12.||Qualified Laboratory Documentation|
|13.||Appearance Approval Report|
|14.||Sample Production Parts|
|17.||Records of Compliance with Customer-Specific Requirements|
|18.||Part Submission Warrant (PSW)|
The customers from the field of automotive industry usually define level of presentation. Namely the fourth edition of the PPAP manual defines 5 elementary levels of presentation. Individual levels differ in extent of presented documents.
It is also defined for the individual documents if they are presented together with the first parts or if they are manufactured and stored by the supplier and presented to the customer only on the basis of his invitation.
How I state above, the extent of presented documentation is usually defined by “Level” fixed by the customer. However, in practise it is often more advantageous not to be content only with the defined “Level” but it is better to clarify the requirements for the delivery of documentation within the process of re-examination of the customer´s requirements. And not only which documents will be presented but also when they will be presented.
Even if you are really from the automotive industry branch, some documents cannot be presented or it is no use to present them. For example, if you do not design the parts and produce them according to the documentation provided by the customer, you do not work out the Design FMEA. If you supply, for example, a rough casting or a forging that your customer machines, it is no use to present Measurement System Analysis because the results will most likely be unsatisfactory. The reason is not caused by the choice of a bad gauge or by no competent operators but it is because measured figures will have a larger range of scatter caused by big surface roughness.
If you are from another branch, on the contrary you can meet requirements to give evidence of other documents than those that are parts of the classic automotive industry PPAP. The most often it concerns requirements for documents proving qualification of employees (workers certificates for non-destructive testing, certificates of welders, etc.). It can also be reports of NDT (non-destructive testing) exams, reports from various production processes (as for example heat treatment and requirement to give evidence of the temperature curve), documents proving health friendliness and other specific documents.
The customer can also require to present approval of such documents as for example: instructions for heat treatment, instructions for non-destructive testing, procedures of welding, instructions for surface finish, packaging instructions, etc.
Here we come to another important task and that is to clarify with the customer WHEN we will present to him the individual documents. Just the instructions and the methods are presented, in most cases, to the customer to be approved even before the start of production of the first parts. Likewise, the customer relatively often requires, before the start of production of the first parts, presentation of the Process Flow Diagram, the Process FMEA process and the Control Plan. On the contrary, sometimes you cannot provide some document even with the first trial parts. It concerns especially cases when the first parts are produced in units of pieces, for example 5 pieces. In such cases, it is hardly possible to elaborate the Preliminary Process Capability Study. You can agree with the customer to present the study only after the production of the first pre-series or series.
What is the simplest way how to deal with the PPAP?
I recommend to set up a form with the list of documents that the customer can require and that you are able to put forward with the first parts. If you are from automotive industry branch, you will probably work with a form where the list of documents will be based on the above mentioned table. If you are from another branch where there are requirements to provide also other documents, you can set up a form that will be somewhat more different from the automotive industry one. You can find a model of such a document here: PPAPform1
Within the process of re-examination of the customer´s requirements, you will then clarify with the customer (except all technical requirements for the part) also requirements for the presented documents. Information to the form is stated by the person communicating with the customer and making clear all the details necessary for production of the new parts. It is usually a saler manager responsible for a given customer or a part. If you co-operate with the customer in the long term, the requirements to provide the individual documents for the first parts can be fixed in the Quality Contract or in the Quality Manual for Supplier (provided to you by the customer). Nevertheless, you issue the form with the list of required documents practically each time because it is the part of the PPAP documentation file and it is something like a “pattern” or a “cover list”.
The next step is to assign persons responsible for working out or ensuring the individual required documents and handing them over the information about the task. If you use company software for planning of contracts and the whole process of preparation of the production where you assign requirements and responsibility for processing of the individual documents, you will make use of it. If it is not possible to assign these requirements to the company software, you can once again use a form where you set deadlines and responsibility for working out or for ensuring the required documents for the first processed parts. You can find a model of the document here: PPAPform2.
It is no less important to assign a responsible person that will complete the documents to the PPAP file. It can be a sales manager or a quality engineer responsible for a given customer.
This person requires delivery of the documents in requested deadline from the individual persons and carries out control of the supplied documents at least in formal aspect. For example, if material certificates are really material certificates from which the first parts were produced. He also ensures the customer will receive the requested documents in time.
The complete file with the requested documents is sent to the customer with the first parts. In the company, you keep copies or originals of those documents the customer required to be elaborated but wants to archive them in your company and to provide them only on the grounds of his later demand. Insert into this file also the document about the approval of the first parts by the customer because only after the approval by the customer the whole Production Part Approval Process is concluded. The file can be, of course, in the electronic form as well.
Only for completeness, I mention there are customers who send you an Excel file with patterns for most of the documents on individual pages and you only fill in.
How I have already indicated at the beginning, these days the PPAP is becoming a standard matter in various branches. And even though it is an uninteresting paper matter, in most cases it is not possible to avoid it if you want to supply your customers with your products.