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Dimensional accuracy is essential in industries where tight tolerances are required, such as automotive, aerospace, and medical.

It can be achieved through proper material selection, mould design and construction, process optimisation, and quality control measures. Regular maintenance and calibration of the mould tooling equipment also plays a critical role in ensuring dimensional accuracy throughout the production process.

What are the Potential Drawbacks of Poor Dimensional Accuracy?

Failure to achieve correct dimensional accuracy can lead to a variety of problems for customers, manufacturers, and end users. These problems can ultimately lead to negative implications for cost, reputation, and the integrity of the final product or component parts.

Let’s consider some of the potential drawbacks of poor dimensional accuracy in more detail:

Compliance and safety concerns: Parts that do not meet dimensional accuracy may not adhere to safety standards or regulatory requirements, potentially leading to legal issues or product recalls.

Increased costs: Re-work and scrap rates may increase due to parts that do not meet dimensional accuracy, resulting in higher production costs and reduced profitability.

Negative impact on brand reputation: Customers may perceive products with dimensional inaccuracies as lower quality, leading to negative implications for brand reputation and customer trust.

Tips to Help Ensure that Dimensional Accuracy is Achieved

There are various ways to ensure that dimensional accuracy is achieved. Adhering to each of the below key principles is essential for any reliable toolmaker or injection moulding company. Failure to comply with these factors will likely result in poor dimensional accuracy.

Use accurate CAD software: Designers should use precise computer-aided design (CAD) software to create detailed and accurate 3D models of the part. This will ensure that all dimensions and features are properly defined.

Consider shrinkage: Designers should consider the shrinkage that occurs during the cooling process of the molten plastic in the mould. The dimensions of the part should be adjusted accordingly to compensate for this shrinkage.

Design for manufacturability: Designers should work closely with toolmakers to consider how the part will be manufactured using the injection moulding process. They should design the part in a way that allows for easy release from the mould, minimal warpage, and uniform wall thickness to help achieve dimensional accuracy.

Use high-quality tooling materials: The quality of the injection mould tooling will have a direct impact on dimensional accuracy. Designers should work with experienced tooling manufacturers and ensure that high-quality materials are used to create the mould. This will help to prevent wear and deformation which could affect the final part’s dimensions.

Conduct thorough testing and validation: Before mass production, designers should conduct prototyping and testing to validate the dimensional accuracy of the parts produced using the injection mould tooling. Any discrepancies should be identified and corrected before the production phase begins.

Factors to Consider

Manufacturers can achieve the desired dimensional accuracy in injection moulding processes by controlling the following factors:

Tolerance: This refers to the allowable variation in the dimensions of the moulded part. The tolerance level is usually specified by the designer or customer and is typically expressed as a percentage of the overall dimension.

Shrinkage: During the cooling process, the plastic material will shrink slightly, which can affect the final dimensions of the moulded part. The shrinkage rate is dependent on the type of material being used and can be compensated for during the mould design stage.

Warpage: Warpage occurs when the moulded part cools unevenly, causing it to bend or twist. This can be caused by uneven cooling rates, improper material flow, or inadequate mould design. Controlling warpage is essential for maintaining dimensional accuracy.