Question 1

What CAD design services does Birkett CAD Services offer?

Accepted Answer

Birkett CAD Services offers 3D modelling, product design, photo realistic rendering, technical drawings for manufacture, pipework routing, fabrication design, reverse engineering, rapid prototyping, plastics manufacturing consultancy (injection moulding and thermoforming), and patent support. All services are delivered using SolidWorks Premium and SolidWorks Visualize.

Question 2

Where is Birkett CAD Services based?

Accepted Answer

Birkett CAD Services is based in Brough, East Riding of Yorkshire, near Hull. Services are provided remotely to clients across the United Kingdom.

Question 3

What CAD software does Birkett CAD Services use?

Accepted Answer

Birkett CAD Services uses SolidWorks Premium for all 3D modelling, assembly design, technical drawings, and sheet metal work, and SolidWorks Visualize for photo realistic product rendering. Files can be delivered in native SolidWorks format, STEP, IGES, DXF, or PDF.

Question 4

How much do CAD design services cost?

Accepted Answer

CAD design service costs vary depending on project complexity and scope. Birkett CAD Services offers a free initial consultation to discuss your requirements and provide a tailored quote. Contact Chris Birkett on 07738 337910 or at chris@birkettcadservices.co.uk to discuss your project.

Question 5

Does Birkett CAD Services specialise in plastics design?

Accepted Answer

Yes. Chris Birkett has 30 years of experience in plastics manufacturing, including 15 years of dedicated thermoforming and injection moulding design. This hands-on background means every plastics design is optimised for the real-world manufacturing process — correct draft angles, wall thickness, and demoulding geometry are built in from the start.

Question 6

Can Birkett CAD Services help with thermoforming pattern design?

Accepted Answer

Yes. Thermoforming pattern design is a core specialism at Birkett CAD Services. Chris Birkett designs thermoforming patterns and vacuum forming patterns in SolidWorks Premium, with full tooling drawings ready for your toolmaker or CNC machinist. Visit the thermoforming design page at birkettcadservices.co.uk/thermoforming-design for full details.

Question 7

What is thermoforming pattern design?

Accepted Answer

Thermoforming pattern design is the process of creating the 3D CAD model of the mould — the pattern — over which a heated plastic sheet is formed. The quality of the thermoforming pattern design directly determines the quality, consistency, and cost of every thermoformed part produced from it. A well-designed pattern produces clean, repeatable parts with minimal scrap.

Question 8

What draft angle is needed for thermoforming?

Accepted Answer

Thermoforming patterns typically require a minimum draft angle of 3 degrees on all vertical walls to allow the formed part to release cleanly from the mould. Deeper pockets or textured surfaces may require 5 degrees or more. Insufficient draft is one of the most common causes of demoulding problems in thermoforming production.

Question 9

What materials can be thermoformed?

Accepted Answer

Common thermoforming materials include HIPS (High Impact Polystyrene), ABS, PETG, PET, Polypropylene (PP), Polycarbonate (PC), HDPE, and conductive ESD materials. Material selection affects pattern design — wall thickness, draft angles, and draw ratio all vary depending on the material being formed.

Question 10

What is the difference between thermoforming and vacuum forming?

Accepted Answer

Vacuum forming is a type of thermoforming where a heated plastic sheet is drawn over a mould using vacuum pressure alone. Thermoforming is the broader term that includes vacuum forming, pressure forming, and twin-sheet forming. For pattern design purposes, both processes require the same fundamental design principles: correct draft angles, adequate radii, and controlled draw ratios.

Question 11

How long does thermoforming pattern design take?

Accepted Answer

A straightforward thermoforming tray pattern design typically takes 1-3 days from brief to completed SolidWorks model and drawings. Complex multi-cavity or multi-compartment patterns may take longer. Birkett CAD Services works directly with clients from brief to delivery, so projects move quickly without project manager delays.

Question 12

What files does a thermoforming pattern designer deliver?

Accepted Answer

Birkett CAD Services delivers thermoforming pattern designs in native SolidWorks format (.SLDPRT, .SLDASM), STEP and IGES for toolmaker compatibility, and fully dimensioned PDF technical drawings with all pocket dimensions, draft angles, radii, and surface finish specifications.

Question 13

What is injection moulding design for manufacture (DFM)?

Accepted Answer

Design for manufacture (DFM) in injection moulding means designing a plastic part so it can be reliably and cost-effectively produced in a mould tool. This includes applying correct draft angles (typically 1-3 degrees), uniform wall thickness, properly positioned gates, adequate radii on all internal corners, and avoiding undercuts where possible. Poor DFM leads to expensive mould modifications, sink marks, weld lines, and high scrap rates.

Question 14

What draft angle is required for injection moulding?

Accepted Answer

Injection moulded parts typically require a minimum draft angle of 1 degree on all vertical walls to allow clean ejection from the mould tool. Textured surfaces, deep ribs, or tall bosses may require 2-3 degrees or more. Insufficient draft is one of the most common causes of ejection problems, surface drag marks, and mould tool damage.

Question 15

How do you design ribs and bosses for injection moulding?

Accepted Answer

Ribs should be 50-60% of the nominal wall thickness to avoid sink marks on the opposite face. Boss outer diameter should be 2x the nominal wall thickness, with a core pin to reduce mass. All ribs and bosses need draft angles and generous radii at their base to reduce stress concentration and improve material flow.

Question 16

Can Birkett CAD Services design injection moulding tooling drawings?

Accepted Answer

Yes. Birkett CAD Services produces full injection moulding tooling drawings including part drawings with GD&T tolerances, mould cavity and core drawings, gate and runner layouts, and ejector pin positioning. All drawings are produced in SolidWorks and delivered as PDF and DXF for your toolmaker.

Question 17

What plastics are suitable for injection moulding?

Accepted Answer

Common injection moulding materials include ABS, Polypropylene (PP), Polyethylene (PE), Nylon (PA6, PA66), Polycarbonate (PC), POM (Acetal), HIPS, and glass-filled grades for structural applications. Material selection affects shrinkage rates, wall thickness requirements, and gate design — all of which are considered during the DFM process.

Question 18

How long does injection moulding design take?

Accepted Answer

A straightforward injection moulded part design typically takes 2-5 days from brief to completed SolidWorks model and DFM drawings. Complex assemblies, multi-component designs, or parts requiring extensive DFM analysis may take longer. Birkett CAD Services works directly with clients from brief to delivery, so projects move quickly without project manager delays.

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