Small Part Injection Molding 

Bruin Manufacturing is an ISO 9001:2015 certified manufacturer and has over 70 years of experience in small-part injection molding. We are a custom injection molding company, and we specialize in those technical, more difficult parts.  Bruin offers all services in-house. From help with part design, out to the tool shop, into a molding press and on to packaging and shipping your part out the door, it’s all done in one location! With Bruin's pioneered "lights out" system, we can meet the tightest tolerances, offer design flexibility and produce items with reduced cycle times and minimal labor content.

Our entire production process is unique. We’ve developed high-output automated process lines capable of fabricating parts with a high degree of precision, accuracy, and consistency with minimal operator oversight. This reduces labor needs, a cost reduction we happily pass along to our customers!

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Small Part Injection Molding Capabilities

A “small part” is defined as a part that fits on the palm of one hand while a “micro” part is smaller than a fingernail. The smallest part manufactured by Bruin so far has been 0.05 grams and the smallest tolerance has been less than 1/1000 of an inch. With nearly 60 plastic molding presses with sizes ranging from 25-165 tons, our capabilities include:

  • Small batch to large scale production
  • Automated production
  • Faster production times
  • High repeat tolerance
  • Precision manufacturing
  • High-quality end product
  • Flexible design capabilities

Small Part Injection Molding Benefits 

Bruin Manufacturing runs 24/6 with just one shift with employees in the plant.  The other two shifts are done “lights out” with no employees present.  This keeps our labor cost down and therefore, your part price lower. Other benefits of working with Bruin include:

  • Lower labor costs per part
  • Lower part price
  • Material and color flexibility
  • Minimal finishing requirements
  • Minimal scrap
  • Proven History
  • Engineering expertise and assistance
  • Responsiveness and reliability
  • In-house tooling
  • Secondary operation capability
  • Mold transfer capability
  • 2-shot molding

Small Part Injection Molding Applications

Our services can benefit a variety of industries including, but not limited to:

Bruin Manufacturing Service Capabilities

Bruin Manufacturing is an ISO 9001:2015-certified manufacturer and we offer a full suite of services to take a product from idea to delivery. Our in-house capabilities include:

  • Product design 
  • Mold design
  • Mold making
  • Material recommendation
  • Manual and automated assembly
  • Ultrasonic welding
  • Overmolding, manual & automatic
  • Secure, custom packaging
  • Pad Printing
  • Heat Staking


Headquartered in Marshalltown, IA since 1949

At Bruin Manufacturing, we are the small parts problem solvers. We offer total, integrated custom injection molding services that can meet your needs for quality, time, and price.

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