In plastic injection molding, buildup can cause a multitude of defects, including gloss. Whether duller or shinier than the spec, all over or only on certain areas of the molded part, gloss can cause rejects or scraps, which you’ll want to mitigate.
How to Identify Gloss from Buildup
As you probably know, buildup isn’t the only cause of gloss. Lack of venting, converging material flow, and certain materials, especially cheaper grades, can also lead to gloss issues. For the sake of this blog post, we’re focusing specifically on gloss caused by buildup.
Easy to identify, gloss from buildup typically presents as a type of discoloration. If this looks and sounds like what you’re experiencing, there are two things you can do to get back in line with the gloss spec: use a coating and/or give the mold a cleaning.
Using a Coating
The right plastic injection mold coating can help minimize buildup and improve mold cleaning, which in turn resolves any related gloss issues. Nanoplas carries a variety of coatings. Choose your coating based on the material being molded and preferred application, i.e. in the press on a hot mold or in the tool room at room temperature.
In the Press Injection Mold Coatings
Nanoplas QC™ Quick Cure is designed for all plastics, including thermoplastics, commodity grades, and engineering grades. It leaves a semi-permanent barrier on the surface using nanotechnology, won’t alter final part dimensions, and cures on a hot mold in 10-15 minutes.
Nanoplas HC™ Heat Cure is made with nanotechnology and creates a semi-permanent barrier on the surface of the mold without impacting part dimension. It offers extraordinary plastic or rubber part release and is the longest-lasting of all Nanoplas coatings.
Contact us if you need help choosing a mold coating or to request a free sample. With all Nanoplas mold coatings, follow our proper application guide to achieve the best results.
Cleaning to Remove Buildup
If you’re going to use a coating, per our application instructions, you’ll want to give the mold a thorough cleaning first. To do this, we recommend Mold Brite or Power Clean. The goal is to remove all debris, oil, lubricants, and rust preventatives from the entire surface of the mold, including all the pores and crevices. If either of those two cleaners don’t get rid of everything or you have some stubborn buildup, then we recommend Zap-Ox™, which will also remove rust, oxidation, stains, and more.
If you need to clean a coated mold, use Nano Mold Cleaner. This product is formulated so that it doesn’t remove coatings, helping the mold maintain its performance.
While gloss from buildup can be problematic, with the right coating or cleaner it can also be rectified relatively easily, helping reduce scrap and minimize rejects.
As we move into 2021, we’re already seeing the expected rise in the need for plastic injection molding for medical devices. Plus, due to the COVID-19 pandemic, the demand for medical devices in general continues to grow. As the demand for plastic medical devices increases, so does the need for NSF Listed injection mold cleaners, rust preventatives, and greases.
Plastic on the Rise for Medical Injection Molding
Medical injection molding has an estimated growth rate of 6.5% over the next 10 years for an ever-expanding list of reasons, including unlimited design options, better regulatory compliance, and little to no manufacturing side effects. Along with sustainability and biocompatibility, plastic injection molding is likely to continue increasing for medical devices.
From all types of tubing to prosthetics and more, the versatility and ability to distribute to a global marketplace add to the benefits of the medical industry moving away from metal and toward plastic.
The Importance of NSF
Particularly with medical devices that absolutely must be clean, sterile and safe, using mold cleaners, rust preventatives, and greases listed by NSF is paramount to the plastic injection molding industry. In order to be NSF Listed, products are rigorously tested and must meet or exceed all standard requirements for certification. At Nanoplas, we have five such products that also improve run time and capacity while reducing downtime.
NSF-Listed Products from Nanoplas
Cera-Lube™ Nano Ceramic Grease has a high drop point and incredible wear characteristics that let customers apply a very thin amount that still lasts up to 10 times longer than other greases.
Safe-T-Clean™ is a high-performance cleaner and degreaser with a powerful spray pattern to break up tough build up and clean hard-to-reach areas.
Safe-T-Guard™ prevents corrosion from penetrating your machine. It’s a truly dry rust preventative, so it won’t break down grease and other already-present lubricants.
SYN LUBE™ High Performance Synthetic Grease is designed for the most difficult industrial applications. With antioxidants, extreme pressure and anti-wear additives, and excellent high temperature properties, SYN-LUBE™ meets the most stringent industrial requirements.
Zap-Ox™ is unmatched in its cleaning ability. No other cleaner can remove rust, oxidation, build-up, weld discoloration and other stains like Zap-Ox™.
Request a Free Sample
Try any of our NSF-listed injection mold rust preventatives, cleaners, and greases for free to see first-hand what our products can do to increase efficiency and reduce downtime. Request a Free Sample
Corrosion in plastic injection molds can be a costly headache if it isn’t handled properly. In fact, according to Grand View Research, the injection molded plastics market size in 2020 is $267 billion and is projected to grow 5% through 2027. Considering those figures, downtime caused by corrosion is a huge potential cost. Preventing corrosion in plastic injection molds before it happens, or fixing it before it requires a shutdown, is essential.
A Rust Preventative is Key to Fighting Corrosion
Using the right Nanoplas rust preventative is the best way to fight corrosion and keep your presses running. Corrosion is caused when water, condensations, off-gases and mineral deposits come into contact with the steel of the mold, creating a chemical reaction that ultimately leads to corrosion.
A rust preventative forms a protective barrier on the mold, blocking those substances from interacting with the mold and keeping your presses up and running.
Choosing the Right Rust Preventative
Because not all molds or processes are alike, it’s important to use the right Nanoplas rust preventative to ensure maximum efficiency and productivity. As always, you can request a free sample of our rust preventatives.
Dry rust preventatives go on completely dry and won’t break down grease. Easy to clean, Nanoplas dry rust preventatives are ideal for protection against corrosion and avoiding bleeding.
Mold Guard can be molded through at startup and also contains release properties.
Mold Guard Green features a green tint to give you a better visual on coverage, which helps cut down on superfluous use.
Safe-T-Guard Safe-T-Guard is NSF H-1 listed, goes on dry and will not break down grease and other lubricants that are already on the surface.
Semi-dry rust preventatives give you longer-lasting protection without bleed through, stopping corrosion before it starts.
The Defender’s green tint helps avoid overspray as you can better see the coverage. Its acid vapor neutralizer protects against corrosive materials, including PVC.
The Protector can be used on both warm and dry molds and protects for up to three years.
Get Your Free Sample of Nanoplas Rust Preventative
Request a free sample of a Nanoplas Rust Preventative or any of our products. If you have any additional questions as to what rust preventative may be best for your application, feel free to contact us to discuss.
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.
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.
Ess Tec, a plastic injection molding company in Holland, MI is an excellent example of solving this problem. They were having issues with grease bleeding off ejector pins, leading to excessive scrap, but through a repeatable application process using Nanoplas Nano Ceramic Mold Grease, Ess Tec saw 87% scrap reduction.
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.
This website uses cookies so that we can provide you with the best user experience possible. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful.
Strictly Necessary Cookies
Strictly Necessary Cookie should be enabled at all times so that we can save your preferences for cookie settings.
If you disable this cookie, we will not be able to save your preferences. This means that every time you visit this website you will need to enable or disable cookies again.
