Offering the most advanced powder coating processes
There are applications where direct from injection molding parts serve the intended purpose. But there are end uses for some plastic parts that require the parts to be enhanced following the manufacturing process.
Most of the painting processes used to apply liquid paints to plastics are similar to those used in painting metals. Powder coating plastic injection molded parts, while not as common, can be done – with a solid knowledge of all the variables involved. These include the chemistry and characteristics of various plastic materials, mold specifics, the finished surface of the part, and requirements for preparation to achieve a good, long-lasting bond.
Excellence in powder coating services requires specific knowledge
The powder coating painting process works well for plastic injection molded parts when a powdered plastic is sprayed onto the plastic parts, then UV cured for adhesion to the surface. This curing step is vital to proper adhesion. The chemical makeup of both the powdered plastic and the plastic molded part must be factored to make sure the powder will bond electrostatically to the plastic before UV curing can effectively take place.
Done correctly, powder coating can provide a tough finish that will last on plastic injection molded parts and provide a desirable appearance in virtually any color.
Powder coating services, an effective injection molding secondary process
There are many ways to enhance a part’s appearance and performance following the injection molding process. Films, paint, powdered plastics, even metallic vapors can be used. In some cases, powder coating can bring the most desirable appearance while providing a long-lasting finish.
For more details and finishing options for your injection molding parts, see our list of other Injection molding painting processes.
Our plastic injection molding design experts can help you and your team choose the most efficient and effective painting process that will deliver the results you need for your parts and the desired end product.
Preparing injection molded parts for the powder coating process
While the paintability of each type of plastic material used in injection molding varies, it’s a known fact that part surface preparation can either make or break the success of the adhesion of the two materials – whether powder coating, liquid paint, or other methods are used.
Molecular weights of different plastics, the inclusion of additives in the resin manufacturing process, and the type and rate of the injection molding process used can all alter painting results. But no matter how well these factors are understood, if the preparation of injection molded parts is not handled properly, a good bond will not be achieved.
Failure to expertly prepare injection molded part surfaces can cause more scrap and rework, a costly mistake that no manufacturer can afford. High levels of contamination in the injection molding process, deburring, and extensive overspray are just some of the challenges we’ve developed ways to overcome before beginning injection molding secondary processes.
In addition, the majority of plastics used in injection molding today have a tendency to generate electrostatic surface charges, which attract contamination like magnets. We avoid painting defects and optimize quality by knowing the plastics used and consistently and carefully scrutinizing the entire process.
- When possible, we develop tooling designs modified to downstream painting requirements in the plastic parts
- Designing for as few cutouts as possible helps provide an optimized painting process
- Rounded part edges can be more easily wetted with paint than sharp ones
- Keeping deburring processes to a minimum can help reduce contaminates and optimize the powder coating painting process because residual burrs can lead to contamination all the way into the painting booth
- Keeping tools exceptionally clean is also important, so we don’t allow any excessive buildup of ingredients of the plastics used in the injection molds we use
Other ways we optimize part cleaning for powder coating services
By developing ingredients such as release agents, additives, filler materials and fibers we can dramatically improve the processing and functional characteristics of plastic injection molded parts and their ability to receive powder coating and other paints.
Key to the success of this method is keeping these ingredients off the part surfaces. We’ve developed proven processes and procedures that protect from transfer of these agents to the plastic parts we mold.
Powder coating requires surface energy, and we know how to get it
Many plastics present very little surface energy. Parts created using injection molding processes can exhibit adhesion challenges, if not addressed. Uniform cleaning or pretreatment can be vital in creating a reliable surface for powder coating and other paint processes. Some of the processes we’ve developed for our customers include CO2 snow-jet, plasma and steam cleaning. These processes can reduce costs, minimize the amount of space needed, and even allow for the cleaning process to be part of the painting line.
By increasing the surface energy of plastic parts, we can dramatically improve paint adhesion. This is one of the main reasons we pretreat plastics that are going to be painted.
Another method we can use to prepare plastic injection molded parts for powder coating and other injection molding secondary processes is ionization. The sometimes-unavoidable electrostatic charging of some plastic surfaces can be counteracted by ionization. To prepare for good, solid adhesion in some non-polar plastics, like polypropylene (PP) and polyethylene (PE), we activate surfaces through ionization before painting.
Ionization processes include:
- Gas phase fluorination
- Atmospheric pressure plasma activation
- Corona treatment and flaming
Color matching at its best
Colorants can be added to help develop the perfect powder coating color for your injection molding part, to adjust gloss or provide precise color in your products. We utilize:
- Pantone color matching
- Physical sample color matching
- RAL color matching
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Surface etching for a better powder coating process
Plastic parts are characteristically smooth. To overcome this fact, the surface of the part can be etched, using a chemical agent to create micro-roughness and sticking areas that will provide better adhesion for the paint. Correct etching with solvents requires knowledge and experience.
Other surface etching methods we employ:
- Chemical reaction, including flame-induced oxidation
- Plasma conditioning
- Light-sensitive chemicals, called photosensitizers, followed by exposure to ultraviolet light
- Ozone-generating electrical corona discharge
Adhesion, adhesion, adhesion
Injection molded plastic part surface preparation is vital to any successful painting process. Adhesion is the focus for long lasting finishes. At ICOMold, we have options available that will bring you the best possible end-result and products you can be proud of.
Injection Molding Production Highlights
> Instant mold and part quote
> Low cost, quick build and quality production
> ICOMold's Lifetime Warranty on Production Molds
> Online project management
> Trouble-free part modifications
> No size limitations
> Any commercially available material and surface finish
What is the process for injection molding production?
ICOMold’s instant online plastic injection molding quote and mold frame sharing technology enables us to simplify and shorten both the quoting and tooling manufacturing process for custom plastic injection molding.
- Load your 3D CAD file to get an instant mold and part quote
- Upon order confirmation, ICOMold starts the mold and part order process
- Tooling design review by ICOMold engineers
- Upon design approval, ICOMold begins building your injection mold
- Customer examines samples for approval
- Part production begins
Go to our plastic injection molding and CNC machining case studies page to see how we helped customers on their projects.