Your Guide to Precision Molding

by Alexander J.
Injection Mold

More than a century has elapsed since the first precision molding machine was designed and launched into the market. Today, companies are in technical collaboration with like-minded individuals. Precision mold making is quickly evolving from the hydraulic-driven tools to superior and electrically-driven components.

The Preface

Precision mold making refers to a type of technology of plastic injection molding. It is also one of the most costly and sophisticated processes of molding in the industry.

Usually, the process is not used in the design and development of products in injection molding firms. It is often used in the development of infrequent occasions, especially when product development demands unusually precise forms of plastic.

Important Highlights

As highlighted above, precision molding is a technical process that demands the application of high-quality precision molds as well as machines. This process is different from the conventional injection molding technique. It is most of the time used in replacing high-quality metal parts that most complex geometries cannot replace.  

The precision part of an item is, most of the time, highly dependent on several injection molds and their suitability to successfully meet the engineering requirements.

How precision molding works

Precision molding is influenced by different factors

  • The size of the cavity in the mold
  • The accuracy in the position of the cavity
  • Selection and choice of the materials
  • Number of cavities involved
  • The runner size
  • The  mold design
  • The thickness of the mold
  • General dimensions
  • The engineering of the design

Mechanism of Precision Molding

Precision molding can be calculated using exceptional polymer optics. For instance, if you require a molded plastic part with extreme precision, to help make sure that there is a gap seal, you could do with some precision mold making.

The primary difference between a molded part and a precision part is the material’s tolerance or range in variation. Although most of the injection mold parts come with a tolerance of 0.05, precision molding has an endurance of about 0.02.  

So, if you intend to manufacture a projectile for the military base, you need high precision for it to fit into the firearm. If the application needs precision molding, then this is all you need to know:

Determine the areas that need some precision

Have you established the areas in the material that require mold precision? Since precision molding is costly than injection molding, you should choose tight tolerances for the item being molded before anything else. For instance, if you have a surgical handle, it may only need more precision for a piece that will end up connecting with the pin. This does not apply to the whole handle.

Determining and identifying the get-go’s precise requirements is a viable way of ensuring that you get the type of product you want. In the case of a surgical handle, then the partner in injection molding can advise you to include the required tolerances via tooling right after the completion of injection molding.

Select a material with low shrinkage

You should choose a plastic material with low shrinkage. For instance, polypropylene comes with a shrinkage of about .014. This is a wide range and can make it difficult to hit a specified tolerance.

Bottom Line

Precision molding is a revered technique used in the design and development of aspheric as well as various lens types that happen to be of high quality. While at it, you need to know how to choose the right material for your precision molding.  

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