Material Certification Types
APP uses the following terminology to address certification of materials.
Certificate of Conformance (C of C):
A document supplied by the material manufacturer that specifies that the materials supplied meet the requirements specified (typically the manufacturer's own stated properties). A C of C is typically not signed and it often does not reference purchase order numbers (only lot numbers). A separate document may be required to link them. If received form a distributor or other third party it can link the product to the original manufacturer but will not show full traceability. For many molding applications this type of certification is satisfactory. For aerospace and military applications a Certificate of Analysis with full traceability is usually required.
Certificate of Analysis (C of A):
A document that states that the materials supplied meet the required specifications and has actual test results and methods. It is signed by the testing agency and typically ties to both the lot numbers involved and the purchase order. A C of A almost always has an additional cost and time requirements. Like a C of C, a C of A will not establish full traceability.
While not a different type of certification, either type of certification can help establish full traceability of the material from the material manufacturer to our plant. Full traceability could be several documents showing the complete path from manufacturer through any distributors or third parties. If you need full traceability you must request it at the beginning of the job, optimally at the quoting stage, as it can be difficult or impossible to obtain after the fact depending on the how the material was purchased.
Certification to other Standards
If a certification to a specification is required (ASTM, MIL, FED, MIS, UL, etc.) independent testing is often required unless data sheet properties can be accepted. Testing to meet all the requirements of some standards is quite expensive and many times there are no materials available that meet all the requirements. Older specifications often run this risk as test requirements were based on optimal properties not real world results. Testing can delay shipping of the material.
UL certifications ("Yellow Card") are supplied by the manufacturers on many flame retardant materials. Independent testing of UL requirements is very expensive. In some cases only the material needs to be approved, but in most the molded product itself needs to be tested. The yellow card only tells you that products made with this material can pass product testing, but the final results depend on your design. If you have thinner wall sections than the material is rated for the product may not pass.
Notes
By default APP supplies a Cof C which for most injection molding materials only covers the manufacturer's published specifications.
One solution to mitigate the higher cost of testing is to find a suitable material for the specification, have it tested to make sure it meets the requirements, and for future orders accept the material on a C of C. Testing could be required on a periodic basis. Another solution is to purchase a large lot of material and have it tested. APP can store the material for you usually at no additional cost..
In all situations APP, will help you find the most cost effective solution that meets the requirements for your plastic molding program.