1. Michael Lundbech A/S
Jakob Nielsen, Injection Moulding Specialist.
Requirements specification for selecting plastic materials for plastic parts
Following points should be considered when selecting materials for a plastic part.
1. Background information
2. Batch size
3. Part size
4. Tolerance requirements
5. Part design
6. Assembly requirements
7. Mechanical load
8. Chemical resistance
9. Electrical properties
10. Environmental impact
11. Color
12. Surface properties
13. Other properties
14. Regulatory requirements
15. Recycling
16. Costs

2. Michael Lundbech A/S
Jakob Nielsen, Injection Moulding Specialist.
Requirements Specification – Checklist
Background information:
 Have we developed a similar product ?
 What new features will the product have ?
 Is this just a new size (upscaling/downscaling) of an existing product ?
 Can we modify the geometry of an existing product to create this new one ?
 Does the new product require a radical change of materials ?
 How do the competitors product work ?
 What tests, studies, or reports already exists regarding this type of product
Batch size:
 How many of the components are likely to be produced each year ?
 Which manufacturing methods are most appropriate ?
Part size:
 Is the parts size a limiting factor in the choice of material, production method, or
producer ?
Tolerance requirements:
 Which dimensions are critical, and what are the required tolerances ?
 Would redesigning the product help to reduce the tolerance restrictions ?
Part design:
 Can the product be made in one piece ?
 Which processing methods may be appropriate ?
 What additional functions can be integrated ?
Assembly requirements:
 Can the assembly simplify or improve the functionality ?
 Can assembly lower the manufacturing costs ?
 Which assembly methods are appropriate for the proposed material ?
Mechanical load:
 Is the part design optimal ( in terms of e.g. gate locations ) with regard to the
anticipated mechanical load ?
 Will the part be under constant load ?
 What are the likely normal and peak loads ?
 How long will the product be under peak load conditions ?

3. Michael Lundbech A/S
Jakob Nielsen, Injection Moulding Specialist.
Chemical resistance:
 What chemicals will the component be exposed to under normal and extreme
conditions ?
 What are the likely chemical concentrations ?
 At which temperatures will the component be exposed to chemicals ?
Electrical properties:
 Does the material need to have electrical conductivity or insulating properties ?
 Does the component need to comply with electrical regulations ?
Enviromental impact:
 Will the part be used outdoors or exposed to UV rays ?
 Will it be subject to any other kind of radiation ?
 Is the material affected by atmospheric oxygen ( oxidation ) ?
 Will the part be exposed to water or steam ?
 What will be the range of the service temperature (normal/minimum/maximum) ?
 How long and how often is the part likely to be exposed to peak temperatures ?
 Will the part be exposed to micro-organisms or attacked by animals or insects ( e.g.
rodents, termites ) ?
Color:
 Does the proposed material have an effect on the choice of custom colors ?
 Does the material need to be UV stabilized to protect the color ?
 Does the part need to be painted or metalized ?
 Does the part need to be assembled and color-matched to other colored or painted
parts ?
Surface properties:
 What surface texture should the part have ?
 Is the proposed material suitable for intended surface finish ( e.g. high gloss ) ?
 Is there a risk of sink marks ( e.g. ribbing ) that would need to be hidden with a
matte finish ?
 Does the surface need to be scratch resistant ?
 Does the surface need to be metal coated ?
 Does the surface need to be paintable ?
 Will the plastic surface be printed ( e.g. hot stamp and tampon printed) ?

4. Michael Lundbech A/S
Jakob Nielsen, Injection Moulding Specialist.
Other properties:
 Does the proposed material need to have high or low friction properties ?
 Will the material be able to insulate from or conduct heat ?
 Is the functionality of the component affected by electromagnetic radiation ?
 Will the parts functionality be influenced by the materials linear expansion
coefficient and anisotropic behavior.
Regulatory requirements:
 Will the parts be CE-approved ( electrical regulations ) ?
 Wil the part be FDA or EN approved or meet other food approval standards ?
 Will the part meet medical requirements ?
 Will the part be compatible with human tissue ?
 Should the part be able to sterilized ?
 Does the part need to be flame retardant to a specific classification ?
 Does the material contain any ingredients or additive that are prohibited in the
intended use or environment ?
Recycling:
 What are the recycling requirements ( e.g. return deposit ) ?
Costs:
 What will the kilo price be for the material ?
 What will the component cost be to produce and for the consumer ?