When you encounter rust, oxidation, buildup, discoloration, and other stains in plastic injection molding, you know both your production and your output is going to be adversely affected. You need to halt production so you can properly clean the mold, which further decreases efficiency and output, which has already been impacted by more scrap or rejects.
Causes of Mold Buildup, Discoloration, Rust, and Oxidation
Mold rust, oxidation, and gas stains can be a result of a number of things, but the most frequent culprit is exposure to water or corrosive gases. Improper shutdown of a mold and incorrect drying of the material can also lead to mold oxidation and rust. If it’s a process-based issue, you might be dealing with a too-high melt temperature, too-long residence time, excessive shear rates, poor venting or low-flow areas in the injection barrel or hot-runner system.
Mold buildup usually comes from volatiles leaving the plastic and collecting on the mold surface. When this happens, the part will often have a rough surface. Buildup can also lead to flash and other part defects, all of which can increase scrap and decrease efficiency.
Discoloration is a problem because it creates inconsistency among the parts, potentially creating scrap. Discoloration in the barrel or the mold can transfer to the parts, leading to the problem. Most often, discoloration is caused by poor venting or a too-small mold gate, nozzle, spruce or runner size. Using too much grease or mold release can also lead to discoloration.
Non-Caustic Zap-Ox Removes Rust, Oxidation, Buildup, Discoloration, and More
If you need to shut down to work on any of these issues, the best option for cleaning is Zap-Ox (or the no-grit version, Zap-Ox NG). It’s non-caustic, so it is operator-friendly and will not corrode the metal, and a thin coat Zap-Ox pulls the stain or discoloration to the surface without scrubbing, removing it in just a few minutes.
See Zap-Ox in Action
No matter the cause, Zap-Ox can remove stains in plastic injection molding. To see how Zap-Ox can work for you (with no scrubbing required on most stains), request a free sample today.
Over-greasing in injection molding is one of the most common causes of creating scrap and, potentially, downtime. By developing a standard method of lubricating and using the appropriate lubricant that works best for your specific application, you could see significant scrap reduction and less downtime.
Key Takeaways: Mold Maintenance: End Over-Greasing & Reduce Scrap
Over‑greasing is a major source of scrap — excess lubricant migrates into the mold cavity, contaminating parts and causing avoidable downtime.
Standardized lubrication methods reduce risk — consistent application practices prevent grease bleed‑off and keep molds running cleanly after service.
Choosing the right grease matters — different applications require different additive packages, and the wrong grease can create more problems than it solves.
PDS comparisons reveal performance gaps — reviewing product data sheets helps identify why a grease underperforms and whether a true all‑purpose option exists.
Over-greasing in Injection Molding Can Lead to Contamination
Lubricating a mold might seem intuitive at first, but it’s not as easy as simply smearing grease on the pins. If you apply too much grease, you could end up with molds bleeding grease for hours and producing only scrap. When too much lubricant gets into the mold cavity, parts can get contaminated and scrap becomes a problem.
Most often, you’ll notice over-greasing when a mold comes back from service, particularly on the moving components. Check all moving parts for signs of over-greasing when a part comes back from service.
How to Achieve Scrap Reduction
There are two things you can do to prevent generating scrap from over-greasing in injection molding and wasting time:
Work with your mold maintenance staff to create a standard lubrication method following manufacturer’s instructions.
Use the right Nanoplas grease, appropriate for your specific application to increase efficiency and decrease the chances for contamination and scrap. For example, Cera-Lube is a food-grade grease that is best for plastic injection molding, off-road and auto racing, steel mills, transportation, salt and fresh water and anywhere there’s exposure to heat, highly corrosive chemicals or water. SYN-LUBE is a high temperature, food-grade grease generally used for plastic injection molds and extreme industrial applications.
Lubricant Application Process to Eliminate Over-greasing in Injection Molding
Clean and remove contaminants off all components before applying.
Apply a small amount with a brush or hand. Spread and wipe off all excess with hands.
Make sure you have a thin film on your wear surfaces.
Install components and work back and forth. Remove components to wipe off extra grease at the end of travel.
Get a FREE Sample of a Nanoplas Grease
Like Ess Tec’s experience shows, combining the right grease with the right application method can drastically reduce scrap and increase efficiency. Get a free sample of Cera-Lube or Syn-Lube and see the difference for yourself. If you’re unsure which lubricant best fits your application, contact us and we’ll make a recommendation.
Injection molders around the world are striving to make their operations more efficient, and more productive. One area that is often overlooked when it comes to gaining such advantages is mold maintenance.
While applying the cleaner, rust preventative, and grease, take the time to thoroughly inspect the mold. Doing so will give you the chance to identify problems or wear on the mold before they become significant issues. As part of your maintenance log, make a note of any concerns, address the ones you can, and track the progression of any issues you can’t fix.
When it comes time to get the mold back into production, products used to clean and prepare the mold should not be a problem or cause a delay. The Nanoplas line of products are formulated to mitigate this issue. They do not cause bleeding or startup scrap, so you can mold right through them and save time getting the production run moving.
Integrating a maintenance program as a core element into your production strategy may allow you to realize significant gains in productivity by reducing startup issues and downtime, making your operation more efficient and profitable. To learn more about how the Nanoplas family of products can play a role in that strategy, contact us today.
Undesired bleed out in injection molding can be caused by—and lead to—a number of problems. One of the most common injection molding defects caused by bleeding is splay, which is often the result of an over-lubricated mold
Syn-Lube™, which breaks down differently than other greases and helps eliminate bleeding, when applied properly, could be the solution to any issues you’re experiencing with splay.
What is Splay?
Silver or white streaks appearing on the surface of the part often indicate splay in injection molding. Several other defects, like scuffs, flow lines, surface scratches, delamination from contamination and flaking, can resemble splay, so it’s important to determine the cause of the streaks as the first step in troubleshooting.
When the cause is from bleeding, you’re probably looking at splay, potentially from a mold with too much lubricant or grease.
How Bleeding Can Cause Splay
If the splay shows up immediately after getting the mold from the tool room, it’s likely the result of too much grease being applied to the mold. When a mold is over-lubricated, grease from the lifters and ejector pins may bleed onto the surface of the part, which then leave the silver or white streaks indicative of splay.
Sometimes, grease can get trapped in the mold inserts, which also leads to bleeding out.
The proper application of any lubricant is essential. Even better: the proper application of Syn-Lube. Syn-Lube high-performance synthetic grease lasts 10 times longer than competitor products and also doesn’t break down like other greases.
Other greases turn to oil at higher temperatures, which can then lead to bleeding into mold cavities. Syn-Lube is a full synthetic, food-grade grease that can be applied very thinly and will not break down with heat like other greases.
If you’re having issues with splay caused by bleed out in injection molding, try Syn-Lube. Applied properly, it will last longer and resist breakdown into potential bleeding.
Coronavirus-related restrictions are beginning to ease up in Michigan and other states, so many sectors are getting back to work. Manufacturing is notably among them, and by extension, plastic injection molders. With employee safety top-of-mind, many plastic injection molders, whether voluntarily or by legal decree, are limiting the number of people that can be on the floor each shift. This likely means less operators working at any given time, so there’s more pressure to maximize production with the staff you do have.
Getting back up and running as quickly as possible and minimizing downtime will be crucial as plastic injection molding for manufacturing not only returns, but ramps up. Be ready and make the most of your workforce by taking this advice to speed startup and cut downtime.
Expedite Manufacturing Startup
There are many factors that could impede your ability to start up quickly, but most of them can easily be resolved.
If your plastic injection molds arerusty due to improper shutdown, clean them with Zap-Ox™. Without scrubbing, Zap-Ox will remove rust, oxidation, build up, weld discoloration, and more.
If a hasty shutdown has left your mold dirty, use the Nanoplas cleaner that meets your needs. All of our cleaners have a stronger spray and chemical composition, so you can clean your molds quicker without having to wipe with a rag, preventing dirt and grime from being pushed back into the metal, and saving time.
If you over-applied a rust preventative because you didn’t know how long your molds would be in storage, or have an excessively thick application of rust preventative, start by using a Nanoplas cleaner. Going forward, use Mold Guard™, Mold Guard Green™, or Safe-T-Guard™ which are thin and truly dry rust preventatives that don’t allow corrosion to penetrate, and can be molded through at startup.
Reduce Machine Downtime
If your plastic injection molds aren’t running, that means you aren’t producing. Keep them in service and working efficiently by avoiding these common issues.
Over-applying grease to make it through a run, because your grease is breaking down with heat. You’re likely trading one problem for another — you’re not coming up short, but you are experiencing grease bleeding into the mold cavities. Either Nanoplas grease will solve both issues. Our greases don’t break down, so there’s no bleeding. They also remain on the surface longer, extending production up to ten times longer than PTFE lubricants, so you don’t have to stop to reapply. In fact, Syn-Lube helped one manufacturer go from daily to weekly applications, and 1,000-1,500 parts per day to 24,000 parts.
Excessive mold release build up. With efficiency being so important due to fewer operators and machine up time, making sure the molds do not have to be shut down for any reason is critical. Excessive mold release build up can lead to temporary shut down for cleaning. Nanoplas coatings and release sprays don’t build up.
If you’re experiencing any of these issues as you and your team return to work, we encourage you to give our products a try. And if you have any other problems related to plastic injection molding that aren’t noted above, don’t hesitate to contact us. We’ve likely heard it or seen it, and solved it before, and will happily do the same for you.
Medical supplies. Food. Even post-COVID-19, both are in extremely high demand and likely will be for the foreseeable future, making medical- and food-grade plastic injection molding extremely busy industries.
Equally in demand is food-grade packaging. As a lasting result of COVID-19, it all ties back to safety. Single-serve products help minimize cross-contamination. Plastic-contained bites keep the virus on the surface of the container, minimizing the risk of diseases getting into the food and therefore into someone’s body.
All this adds up to an increased need for medical- and food-grade plastic injection molding. To step up and help meet this demand, there are three things you and your team can focus on: production efficiency, scrap reduction and startup.
Key Takeaways: Tips for Increasing Production in Medical- and Food-Grade Plastic Injection Molding
Medical‑ and food‑grade injection molding demand remains elevated, driving the need for higher throughput and more reliable mold performance.
Nano‑thin coatings like HCF™ improve release, extend cycle life, and reduce downtime tied to mold cleaning.
High‑performance greases such as Min‑Lube™ minimize scrap by preventing bleed‑off into cavities and extending lubrication intervals.
True dry rust preventatives like Safe‑T‑Guard™ support faster startups and protect molds during storage without breaking down lubricants.
Maximizing Injection Molding Production
To make your runs as productive as possible, you need to release as many products as you can while minimizing downtime. Applying a nano-thin coating when the mold is out of the press, like HCF™ Heat Cure FDA Compliant, is a good first step. It offers extraordinary release, up to 300,000 cycles, and eliminates the need for traditional mold releases that build up and require shut down for cleaning.
Minimizing Scrap
If you use a grease that doesn’t break down, you’ll significantly minimize, and possibly even eliminate, scrap from bleeding into the mold cavity, injector pins, and other areas. Applied correctly, Min-Lube™ (high performance, nano ceramic grease) mitigates bleed off. It remains on the surface longer than PTFE lubricants, extending production time up to ten times longer. In fact, Min-Lube helped one manufacturer go from 1,000-1,500 parts per day, to 24,000 parts, with the product lasting weekly versus daily.
Speedier Startup
When it comes time to store your molds, use a dry rust preventative, like Safe T Guard™. Unlike other rust preventatives that claim to be dry, Safe T Guard truly is, so it won’t break down grease and can be molded through at startup, getting your production up and running faster and reducing scrap significantly.
If the onset of COVID-19 and related quarantine orders didn’t give you time to properly store and maintain your molds, a cleaner like Zap-Ox™ will have them back in operating form ASAP. Zap-Ox cleans gassing and burn marks, buildup, and more with little-to-no scrubbing, saving maintenance and downtime.
Note that all Nanoplas products mentioned above are FDA-compliant or NSF-registered, making them appropriate for medical and food-grade plastic molding.
Whether you increase production by focusing on one, two, or all three of the areas discussed, or are trying to maintain the same output with less staff due to health and safety measures, we here at Nanoplas want to help, so don’t hesitate to contact us. We’re happy to provide a free sample, product recommendation, or answers to any questions you might have.
