Common Injection Molding Expectations
Common Injection Molding Expectations
Interactive Model of Common Plastic Injection Expectations
Plastic injection molding is well regarded for being a highly efficient and rapid production process. Utilizing our long-term relationships with many material suppliers we are able to offer nearly limitless options for materials. This access to materials allows product to be flexible or rigid, soft or hard, rough or smooth, and more. Complex geometries can be injection molded that would otherwise require labor intensive machining techniques or simply cost too much to produce. There are several common characteristics that this interactive model demonstrates and you will now be able to identify injection molded characteristics all around you. While this is not a complete list of all possible characteristics, it will help show and explain those most common to the injection molding industry.
- Flash
- Pin Witness
- Flowlines
- Sink
- Knit Lines
- Warp
- Parting Lines
- Sprue Mark
- Gate Mark
- Sub-Gate Mark
- Gate Blush
- Gas Burn
- Voids
To begin select a characteristic above, and then view the 3D model examples below:
Flash is a thin portion of excess material on an injection molded product. Flash can occur when a cavity is filled with excess plastic or if the tooling requires maintenance. Light flash can just be an aesthetic issue, but excessive flash is easily trimmed. If present, our process technicians are trained to identify and remove flash.
A pin witness is a depression left on the product by the ejector pins that push the product out of the tool. These are also known as ejector pin marks. Our in house tool-designers and tool-makers have many options if these features are undesirable.
Flowlines are a visual representation of the plastic flow path in the cavity of the tool. They can occur due to the speed in which plastic enters the mold. Flowlines are primarily cosmetic in nature and can be minimized by our experienced process technicians or eliminated with proper tool/part design.
Sink refers to an area of a molded product that appears to be sunken. Sink commonly occurs in products with non-standard thicknesses or variable wall thickness. Sink can be visually unpleasing and sometimes problematic for use. It is typically resolved with proper part design or adjustments of machine parameters.
Knit lines or weld lines are hair-like lines that appear on the surface of a part where material has converged while filling the cavity of the mold. Similar to flash, knit lines may be only an aesthetic issue or problematic in extreme cases. The location can be identified and relocated by adjusting the gate location or often reduced by adjusting machine parameters.
Warp is a conflict of internal stress in a product when a cooling differential is present. In areas where a product is intended to be straight, it may have a curve instead. If excessive and causing product functionality issues, warp is usually corrected with temperature or timing adjustments during molding.
Parting lines are a thin protrusion of plastic on the product. Parting lines are most commonly located where the injection mold tooling halves meet to form the product cavity. Usually a minimal concern other than being visually displeasing, parting lines can be reduced with proper mold design and/or machine parameter adjustments.
The sprue is the orifice that plastic material flows through while being injected into the mold. In the event that the sprue fills the cavity directly, the sprue is later trimmed, leaving a circular witness on the product. Often our experienced technicians will remove this feature leaving a clean machined surface. Alternatively, the location can be chosen in a manner that would be hidden from plain sight.
A gate mark appears as a rectangular witness on the product at the parting line. This witness is the remnants of the gate that has been trimmed from the product. Rarely a functional concern, gate/sub-gate marks are placed in a location that will properly fill the cavity. If that location is undesirable on the finished product, a different location may be used.
A sub-gate mark appears as an oval witness on the product below the parting line. Rarely a functional concern, gate/sub-gate marks are placed in a location that will properly fill the cavity. If that location is undesirable on the finished product, a different location may be used.
Gate blush is recognizable by a cloudy or hazy appearance surrounding the gate mark. A high material shear rate is commonly the culprit and gate blush is cosmetic in nature. This can be minimized or eliminated with proper tool/part design and machine parameter adjustments..
Gas burn marks appear as discolorations on the product, usually black or rust-colored. Gas burn is a feature in product areas that have been subjected to high pressure causing the gas to superheat and combust. These locations are often easily identified and the tooling can be vented to correct the issue. If present, our process technicians are trained to identify gas burns and take necessary action.
Most commonly found in relatively thick cross sections, these features are typically sub-surface. A void can be present as a result of the product trapping gas in the cavity and appear as air bubbles. These features are eliminated with proper part design or allowed if the product function is uncompromised.
Using your mouse (or fingers if on a mobile device), you can rotate the part to reveal each defect and zoom in for a close-up visual image and description of each characteristic.
PREVIEW
Dan & The Entire Production Staff at DPI,
I hope this message finds you well. On behalf of everyone at McClain Oil Tools, I want to express our sincere appreciation for the exceptional work and commitment your team has demonstrated in manufacturing our parts. Over the years, your consistent quality, attention to detail, and reliable delivery have been instrumental in helping us meet the needs of our clients.
We genuinely value the partnership we’ve developed with you. It’s a pleasure working with a team that shares our high standards and commitment to excellence.
Once again, thank you for all your hard work and support.
- Lauren McClain Owens, President, McClain Oil Tools
Read MoreDPI has helped us with many difficult projects over the years through engineering, prototyping and production. This has helped our customers solve issues in their end product, and save on project costs.
With Diversified Plastics ability in converting protype machined parts to injection molded production runs. Quantities ranging from tens to hundreds and thousands they have been by our side.
They have a very diverse set of manufacturing capabilities and are capable of many different manufacturing methods from gear cutting, protype tooling, molding of polyurea’s as well as epoxies. Precision machined parts to large diameter large footprint near net shape cast nylon parts finished machined as a secondary operation on their CNC equipment.
Their ability to truly injection mold UHMW parts sets them apart from everyone!
Large machined parts, precision 5th axis components, and secondary operations such as vapor polishing, installing inserts, bonding plastic to steel, welding, gluing and forming.
No matter the size of the project, Diversified Plastics has always been extremely responsive and been able to accommodate our quality needs. Coupling their outside of the box thinking with their many capabilities has yielded many wins for both our companies and our customers.
Yes, their “outside of the box thinking” is one of their strongest assets. They do not spend much time on the phone telling me why they can’t do something. They spend that time internally finding ways to make that project work for Curbell Plastics and our customers.
Read MoreDiversified Plastics has become an integral working partner with us at McClain Oil Tools. Steve Kirgan has been working with us since 2014 to make sure our needs are met. From communication to the exceptional parts we buy, everything is top notch. Any issue that has come up has been resolved in a timely manner. We are grateful to continue to grow alongside Diversified Plastics.
- Lauren McClain-Owens, Co-Owner, McClain Oil Tools
Read MoreOur sprockets arrived today! Please thank the entire Diversified Team that helped get this order out to us on such short notice. Thanks again for such outstanding customer service!
- Scott Locke, Maintenance Superintendent, Montrose Forest Products
Read MoreDiversified Plastics is a great company with a great staff. I had issues sourcing parts for an OEM and they really came through. We had a lot of custom parts made out of special material and they found a way to get it done. The parts were both on time and made perfectly.
We use a lot of anti-static UHMW and adhesive backed material and I have never had an issue with quality or price. They have an amazing array of capabilities from raw material to highly machined parts.
I have used them to waterjet, router, machine, and extrude many parts for my OEM without any issues. I highly recommend Diversified Plastics! Luke is my salesman and he is extremely knowledgeable and great with customers. I will continue to use them for all my plastics needs.
- Kevin Martin, Account Representative, Motion
Read MoreI have worked with DPI and Luke Vonlanken on at least 18 injection molding products in the past 3 years.
From the very beginning, DPI is there every step of the way from application, engineering meetings (as many as needed), 1st articles, part approvals, and tooling adjustments. They are easy to work with, they communicate flawlessly, and they keep you up-to-date on open projects so you can focus on your work without the worry of missing timelines.
With their help, I was able to sell a customer on the benefits of injection molding rollers out of glass filled nylon rather than buying imported phenolic rollers from China. Our customer is thrilled with the results. They appreciate getting a finished part they can immediately install without secondary machining options instead of the hassle of imported phenolic rollers with tolerances so large that they have to machine every part after they get them in. They are saving money and time with rollers from DPI.
I consider DPI a valued partner and I truly trust them, reaching out to them for any new opportunities I come across.
- Dennis Crandall, Territory Manager, Alro Plastics
Read MoreDiversified Plastics really lived up to their name. I needed a unique plastic for a specific application in the amusement ride industry and the team at DPI took the challenge head on. They were able track down a exotic blend and get the parts manufactured in time for our field testing. Even though we were a small order in a niche market, DPI took our problem seriously and delivered results.
- Will Rockett, Wiegand
Read MoreAs a vendor partner for fabrication, injection molding, and precision machined parts, Diversified Plastics has supported Curbell Plastics in helping us create new business with new customers. DPI has helped us with many difficult projects over the years through engineering, prototyping, and production. This has helped our customers solve issues in their end product and save on project costs.
We value Diversified Plastics’ ability in converting protype machined parts to injection molded production runs. They meet our needs whether it’s quantities ranging from tens and hundreds to thousands. They have a very diverse set of manufacturing capabilities and are capable of many different manufacturing methods including gear cutting, prototype tooling, and molding of polyurea’s as well as epoxies.
Their ability to truly injection mold UHMW parts sets them apart from everyone! We also trust them for large machined parts, precision 5th axis components, and secondary operations such as vapor polishing, installing inserts, bonding plastic to steel, welding, gluing and forming.
No matter the size of the project, Diversified Plastics has always been extremely responsive and been able to accommodate our quality needs. Their out-of-the-box thinking coupled with their many capabilities has yielded many wins for both our companies and our customers. Yes, their “outside of the box thinking” is one of their strongest assets. They do not spend much time on the phone telling me why they can’t do something. They spend that time internally finding ways to make projects work for Curbell Plastics and our customers.
- Tim
Read MoreOvivo has worked with Diversified Plastics for many years now, creating a good relationship and partnership. Diversified is a company with a lot of integrity, positive responsiveness to their customers, and good quality products. They are always there to support the different projects that Ovivo has to manage and I can only recommend to purchase products from Diversified Plastics.
- Philippe Rateau (Buyer/Planner/Estimator)
Read More
Need Support?
When you know what you are looking for or want to start with an idea, we are ready to help. Please reach out and we will start you on your path to plastic solution success!
