top of page
Wedge Whiteboard 3D CAD drawing used to show the final product
Red polypropylene moulding for the end of a wedge whiteboard

Paul Norman Plastics (PNP)

Design for Manufacture Services (DFM)


Proven track record in toolmaking and plastic injection moulding.


ISO 9001 Certified: Guaranteeing high-quality products and processes.


Ensuring your success through competitive pricing, on-time delivery, and transparent communication.


Explore how our four decades of diverse industry experience can benefit you.

Streamline Costs and Efficiency from the Outset

Design for Manufacture (DFM) is the cornerstone of creating cost-effective products. By considering manufacturing capabilities and limitations during the design phase, DFM streamlines production reduces costs and ensures high-quality output.


Explore our DFM services to see how we can help optimise your designs for efficient and economical manufacturing.


During your initial consultation, we can review your designs and product specifications and offer advice on the following:

  • Material Selection: Guidance on choosing the most suitable polymers for your plastic parts.

  • Design Simplification: Advice on reducing complexity to improve manufacturability, including:

    • Runner and Gate Design: Optimise the design of runners and gates to reduce excess material usage—use hot runner systems to minimise waste by eliminating the need for runners.

    • Wall Thickness: Advice on ensuring uniform wall thickness to prevent issues like warping, sink marks, and uneven cooling.

    • Ribbing and Reinforcements: Advice on adding strength through ribbing and reinforcements without significantly increasing material usage.

    • Weight Reduction: Advice on reducing material usage and weight by hollowing out sections while maintaining structural integrity.

    • Draft Angles and Transitions: Advice on incorporating appropriate draft angles and smooth transitions to facilitate easy part removal from the mould.

    • Undercuts and Side Actions: Advice on minimising undercuts and the need for side actions to simplify mould design and reduce complexity.

  • Mould Flow Simulation: Use mould flow simulation software to predict how the plastic will fill the mould and identify potential issues with part geometry.

  • Prototyping: Arrange for prototypes to validate the design and make necessary adjustments before full-scale production.

Yellow A3 Wedge double sided whiteboard being assembled
Blue polypropylene component with over moulded TPE rubber foot

These services are designed to ensure that your products are optimised for efficient, high-quality, and cost-effective manufacturing from the very beginning.

Unlock the Potential of Design for Manufacture

with Paul Norman Plastics.


Contact us today to learn more about our DFM service and discover how we can help you streamline production of your plastic component parts.

  • What is Design for Manufacture (DFM) and why is it important?
    DFM is the process of designing products for ease of manufacturing, reducing costs, and ensuring high-quality production.
  • How can DFM principles be applied to my injection moulding project?
    DFM principles can be applied by optimising part geometry, material selection, and mould design to improve manufacturability and reduce costs.
  • What are the key considerations in material selection for injection moulding?
    Key considerations include mechanical properties, thermal properties, chemical resistance, and cost.
  • How does wall thickness affect the injection moulding process?
    Uniform wall thickness is crucial to prevent warping and sink marks and ensure even cooling and solidification.
  • What are the benefits of using ribbing and reinforcement in part design?
    Ribbing and reinforcement can add strength and rigidity without significantly increasing material usage.
  • Why are draft angles important in injection moulding?
    Draft angles facilitate the easy removal of parts from the mould, reducing the risk of damage and ensuring smooth production.
  • How can I minimise undercuts and the need for side actions?
    To minimise undercuts and the need for side actions in plastic injection moulding, you can redesign the part geometry to eliminate overhangs, use sliding shutoffs, consider split moulds that open in multiple directions, incorporate inserts for undercut features, and employ collapsible cores that retract within the mould. These strategies simplify the mould design and reduce the complexity and cost.
  • What role does mould flow simulation play in the DFM stage?
    Mould flow simulation helps predict how the plastic will fill the mould, identify potential issues, and optimise part and mould design before production.
  • How can I optimise runner and gate design to reduce material waste?
    Optimising runner and gate design, including hot runner systems, can minimise waste and improve material efficiency.
  • What is the impact of production volume on tooling and part design?
    Production volume affects tool design, material selection, and cost-efficiency strategies; high volumes may justify more complex tooling for long-term savings. Adding additional cavities for example.
  • How can DFM help in identifying potential cost savings?
    DFM helps identify cost savings by optimising part design, reducing material usage, and simplifying the manufacturing process.
  • What are the common pitfalls to avoid during the DFM stage?
    Common pitfalls include inadequate draft angles, inconsistent wall thickness, poor material selection, and overly complex designs that complicate manufacturing
  • Can design changes be made after the DFM stage?
    Yes, design changes can be made, but finalising the design during the DFM stage is more cost-effective to avoid costly modifications later.
  • What is a projected area and how is it relevant in manufacturing?
    A projected area is a two-dimensional area measurement of a three-dimensional object projected onto an arbitrary plane, important for determining material and size limitations.
  • What is a draft angle and why is it necessary?
    A draft angle is a taper applied to the faces of a part to prevent them from being perpendicular to the mould tool opening, essential to avoid damage during ejection. Recommended draft angles range from 0.5 to 5 degrees depending on the situation.
  • Why is uniform wall thickness important in injection moulding?
    Consistent wall thickness helps in even cooling, reducing warping and shrinkage. However, for adjoining ribs and other features, maintaining a thickness of about 2/3 of the main wall thickness is recommended to prevent sink marks. Consistent wall thickness will also aid smooth flow of material during the injection phases.
  • What are the best practices for avoiding sharp corners in moulded parts?
    Avoiding sharp corners is recommended as they can be points of weakness and may increase tooling costs. Using radiused corners is preferred.
  • What surface finish options are available for moulded parts?
    Surface finishes range from non-cosmetic (visible machining marks) to various cosmetic finishes, including polished surfaces and specialty textures.
bottom of page