What is Transfer Molding?

Published on October 10, 2023

When a company receives an injection mold from a customer or another company on behalf of a customer, there’s a certain amount of mystery as to why a transfer is taking place. Molding companies sometimes receive customer requests to use existing molds that they provide for production, but often, the reasons behind this aren’t exactly clear. By understanding what is transferred, molding hardware can then be used for its designed purpose: making injection-molded components and other products made via injection molding.

(If you’ve come here to understand the process referred to as transfer molding, you’ve unfortunately come to the wrong place. We’re looking at the transfer of molds from one entity to another and not “what is transfer molding.” So, if you were trying to answer the question “What is transfer molding?” it’s best to look here.)

What is Transfer of Molding Hardware and What It Involves

A mold transfer occurs when a mold built and used by one company is transferred to a new manufacturer. There may be various motives for this, and the reason may not even be planned. It might simply be that the manufacturer is no longer suitable for the mold owner’s needs. For example, a company focusing on producing prototypes may be unable to do larger production runs. Another reason may be that an injection molding company simply goes out of business, so the manufacturer needs the mold transferred to another business that can use it for production.

However, transferring an injection mold might limit its use somewhat. Is transfer of molding infrastructure from one company to another common? It’s more common than many think, and there are numerous reasons why it sometimes takes place. In short, a situation may follow a general pattern that makes another company responsible for production and, thus, the molding hardware.

Situations might include when:

  • An importer pays a supplier of injection molds to build one to produce a batch of molded products.
  • For whatever reason, the importer wants to end its relationship with the mold supplier for many reasons, such as bad attitude, delays, price, or quality.
  • This importer then finds another qualified mold supplier but rightly doesn’t want to pay for another mold, as making a mold is expensive.
  • The qualified mold supplier now has a mold developed by another company, yet the new supplier also needs to understand what the transfer of molding tool meant to accomplish.

When transferring a molding apparatus to another provider, it’s important to understand why the mold is being sent elsewhere. The new injection molding company will likely have very little insight into what is involved in this transfer. Mold creation involves a lot of thought, including design choices, how workable the mold is, and whether sufficient maintenance has been done to keep the mold in good condition. For these reasons, a new manufacturer must understand why a transfer of molding hardware is taking place.

Considerations for Transferring Molds

Five major issues should be addressed when transferring a mold and other injection molding equipment from one supplier to another, though the information provided by the company doing the transferring may be somewhat limited. Is the transfer of molding hardware done in a way that will ensure everything has been assembled properly, the molds aren’t damaged, and all components are properly functioning?

#1 – Is the Transferred Mold Assembled Properly?

To ensure that there’s no problem with assembly during a mold transfer, inspecting the mold’s assembly closely and thoroughly is important. While a client may be upfront with a new supplier and describe the mold as problematic, sometimes it only requires a simple adjustment to resolve what may seem like a complex problem. For example, after cleaning and inspecting a mold, the new supplier may find that ejector pins weren’t properly installed. In this case, reconfiguring the mold may simply involve disassembling and then reassembling it, after which it should operate satisfactorily.

#2 – Is There Damage to the Mold?

More laidback injection molding companies may just state that they no longer want to do production runs with a specific mold due to it being damaged. Careful inspection by another supplier may show that a simple component was damaged, which can be replaced. Again, can be as simple as an ejector pin or addressing mold venting to get a more stable process. Often, after replacing a broken part or making a minor tweak to a cavity, a mold will have plenty of useful lift left.

#3 – Are Mold Components Functioning Properly?

An injection mold is part of a complex production system requiring numerous components to interact harmoniously. A mold technician won’t see every part of a mold as it performs its task within the injection molding process. Understanding whether a mold functions as it should requires isolating each step involved and ensuring every component interacts appropriately with its other parts, including how it moves. The mold debugging process involves several steps.

This includes looking at these two very basic issues: 

  • Whether a component moves as it should.
  • Whether a component moves in a manner, it shouldn’t.

While a part moving appropriately may not appear to be a problem, it doesn’t necessarily determine there’s nothing wrong, so if there’s a problem with a mold, it’s important to understand exactly what it is. Transfer to molding companies of an injection mold not made by them requires that they look closely at it before using it in production. The problem may just be with cam angles that are off slightly, for which a quick correction may fix any issues. However, it may instead be that the customer is trying to get a second opinion on whether a mold needs to be scrapped or salvaged. For this, it’s important to ask the right questions.

#4 – Are There Any Processing Issues?

If the design of a part isn’t engineered correctly for the material or there are other processing issues, it’s unlikely a mold will produce quality parts in a repeatable process. As this is the very essence of the injection molding process, it’s important to establish a baseline. This can be done through what’s known as scientific molding, a process that looks at all the principles and theories behind the injection molding process and essentially applies scientific methods to it. This includes utilizing scientific data to troubleshoot processes, which are used to augment efficiency, enhance quality, and provide earlier detection of component failure.

Scientific molding processes look at the following issues:

  • Confirm that optimal processing with the mold has been achieved.
  • Develop instructions for a specific mold or molds.
  • Ensure fabrication of components can be done both accurately and repeatedly.
  • Look within the mold’s cavity during the injection molding process to ensure the finished product is of maximal quality.
  • Monitor pressure to detect quality issues early and ensure the repeatability of the process.
  • Use actual readings to describe the finished product.

Using science within the injection molding process adds value by ensuring that any variation in equipment or materials used can be measured to ascertain changes in quality. Unlike the industrial process of injection molding, scientific injection molding relies less on the experience of those involved and more on the data gathered to make it more reliable.

#5 – Do Parts Conform to the Print and Parts Made Previously from Other Suppliers?

This involves the use of a formal method of inspection that includes documentation known as first article inspection (FAI), which verifies that a component’s features follow the customer’s specifications. This is done by comparing previous parts by other suppliers using this same mold. An FAI is particularly important in sectors like the aerospace, automotive, and medical industries, where strict standards exist regarding part performance.

An FAI inspects a part made via injection molding for criteria that include:

  • color
  • density
  • finish
  • material
  • wall thickness
  • weight

While an FAI may look at the first production run of a particular mold, this isn’t always the case, and, in certain instances, more than one component in the run is used for comparison. The FAI gels with scientific injection molding methods provide a representative sample of parts in subsequent production runs. These must also utilize the same methods and materials as previous suppliers that used the mold to make a proper comparison.

Tips on Transferring Molds

When transferring any type of tooling between manufacturers, it can cause friction. The original mold supplier may be unhappy about losing the business, so they have little incentive to be forthright. Though the manufacturer owns it, the supplier may have used the mold for other customers without the mold owner’s knowledge.

Here are a few tips to consider when transferring molds between suppliers: 

  • Contracts: There should be a written contract regarding mold ownership.
  • Design information: Any CAM (computer-aided manufacturing) designs must come with the mold, along with any information regarding mold size, the plastic type used, and injection parameters.
  • Engraving: Having a company name or logo engraved on a mold may help establish its ownership.
  • Explanation: The old provider will want to understand why they’re losing business, so it’s appropriate to politely let them know about any performance issues so that they can correct them.
  • Finances: The old supplier may seek to get one last payment; if it’s only a small payment, it may be more worthwhile to pay a small price for things like storage and maintenance, along with paying for shipment, to maintain goodwill.
  • Inventory: During the transfer between injection molding companies, there will likely be no production, so sufficient inventory should be available to handle demand.
  • Ownership: While an injection molding company may state that the manufacturer owns the mold, if there’s nothing in writing, this can make the matter of ownership problematic.
  • Qualifications: Any new third-party provider should be reliable and able to meet production targets, so due diligence should be performed, including an audit of the new partner’s production facility.
  • Testing: A new supplier will likely charge to evaluate the mold and propose improvements if needed, which is both reasonable and recommended.

Once in the hands of a new injection molding company, there will likely be changes in the exact type of plastic used, along with possible differences in parameters between the old and new providers. As these production differences may affect the dimensions or quality of a product, the mold must be tested before any large-scale production with it resumes.

Transferring Molds to Spaulding Composites

Spaulding Composites Inc. can design and build the mold you need. Our expert team of engineers can create highly complex molds, including the ability to mold unusual shapes, larger workpieces, and tight tolerances. We can also recommend molds built and designed by other molding companies. Contact us today to learn more about mold transferring or our injection molding capabilities.