5 Challenges Working with Injection Molding Suppliers and How to Avoid Them

Injection molding is a large industry with a lot of companies providing this service but not all injection molders are created equal.  Some injection molders niche lies with prototype and low volume manufacturing while others focus on high volume.  Some put a high value on engineering expertise to help clients in product design where others just want a CAD model they can build to.  There are challenges in a customer supplier relationship, and below are a few specific to injection molding.

  1. Problem Solving Difficulty: When problems occur whether it be a quality issue on a part, a last minute order increase, or production delays you need to be able to trust that your supplier can handle these situations, and that they aren’t in over their head.  The key here is to understand the role each party is expecting to play in the problem-solving process. 

A customer should talk about their expectations and probe the supplier for instances where they have met those expectations.  Some clients want to be heavily involved in problem solving with their suppliers and have the structure to support that.  I know another client that is continually frustrated by some of their supply chains lack of resources and expertise to solve basic injection molding problems and therefore shares his staff to help when they are already stretched thin. 

At a minimum, suppliers should be able to contain the problem, identify the root cause, and implement corrective actions without needing the customer to be over their shoulder every step of the way.  Be clear on the role you expect the supply chain to play in problem-solving and how you expect them to execute to achieve that expectation.  Doing so will ensure you are on the same page from the start and prevent costly issues down the road.

  • Recognizing Tight Tolerance Molders from Standard Molders:  If your components need to hold tight tolerances, sourcing that business to an injection molder that does not have the process control needed for tight tolerance molding can create quality issues very fast.  Not all injection molding is created equal, and not all injection molders stay focused on what they are good at and bite off more than they can chew. 

Systems and processes at one company whose niche is high volume manufacturing are going to be different than a company whose niche is prototyping and low volume manufacturing.  The same goes for companies who primarily mold safety functional components versus a company that molds large trim pieces and bumpers.  Understanding what your supplier is good at it before sourcing them business can prevent costly mistakes throughout the product life cycle.  When identifying an injection molding supplier to source high volume tight tolerance business to, there are a few key things to looks for. 

  • Do they implement scientific molding principles when developing the process?  Good tight tolerance molders know the importance of setting up a robust production process and apply decoupled II and Decoupled III molding concepts to achieve this where appropriate.  Ask about their development process to get an understanding if they implement scientific molding. 
  • Do they have a strong process for scheduling production?  A challenge for high volume manufacturing is scheduling production runs to meet multiple client’s delivery needs, be sure to ask to see their on-time delivery metrics and how they manage capacity.
  • Lack of Engineering Expertise:  Some injection molders staff their engineering team to be able to provide value added activities such as product design support and with engineers with a solid knowledge of scientific molding principles to develop processes specifically for tight tolerance injection molding.  Other suppliers who don’t specialize in this type of molding, staff their engineering department to receive a part design, build a mold and run simple parts.  If you need your supplier to be able to develop molds and processes for critical tight tolerance components, ask the supplier about their feasibility process?  Tight tolerance injection molders will have a thorough feasibility analysis that will review the part design for manufacturability and provide design change requests if it means they can build a more robust mold.
  • Quality: Managing suppliers with poor quality is a time-consuming task, and can create strain on the customer supplier relationship, especially if there are persistent issues.  Just like all injection molders aren’t created equal, in terms of competency and capability, their Quality Management Systems (QMS) aren’t either.  A supplier who builds systems and processes around, identifying and eliminating risk, reducing variation and standardizing the operation eliminates many failure modes that lead towards quality issues. 

When evaluating a supplier’s QMS, ask to see their process for non-conforming product.  Suppliers with good quality records will have a process that protects their clients from internal issues and utilizes permanent corrective actions to ensure an issue will not be repeated.  Also determine how they evaluate other processes for risk and perform read across.  Good quality management systems won’t just fix a problem on one part, they will ask the question could this happen on other product, and if it can how do we contain it and correct it everywhere?

  • Communication and Transparency:  Clear and concise communication between a customer and injection molding supplier is paramount to the success of both companies.  A supplier who does not communicate in a timely matter, or worse withholds information purposely, creates friction in the relationship and can ultimately create issues (sometimes costly ones) that could have been avoided if they were transparent.  Customer and supplier relationships need to be about building trust and creating a partnership.  We all want to work with people we trust, and that is the foundation of good teamwork.  Injection molding suppliers that have good communication and transparency will usually exhibit these signs you can look for:
    • They’ll respond quickly with requests, even if it is to state they need more time to provide what is needed.
    • They will be open an honest about quality issues and won’t delay in notifying clients.
    • They won’t provide misinformation and will hold themselves accountable when mistakes happen.

Author:  Adam Smith, President of Millennium Plastics.

Millennium Plastics is a high-volume injection molding company that specializes in tight tolerance molding.  Utilizing the latest technologies and engineering expertise, Millennium Plastics provides best-in-class quality.

To learn more about how Millennium Plastics faces the “5 Challenges working with Injection Molding Suppliers” visit www.millennium-plastics.com.

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