Making Custom Mold Textures with CNC Machining(online machine shop Eden)
- source:DAHLER CNC Machining
In this article, we'll look at how CNC machining can be used to make molds with custom surface textures. We'll cover the benefits of custom textures, different techniques for creating textures, and how to design parts that take advantage of textured molds.
Benefits of Custom Mold Textures
Custom textures allow plastic parts to have unique visual and tactile properties. Some key benefits of textured molds include:
- Unique aesthetic - Textures like wood grain, fabric patterns, and more can be replicated. This allows products to stand out.
- Enhanced grip - Parts can be molded with tactile textures for better grip and handling.
- Branding - Textures can reinforce branding by mimicking materials tied to a brand's identity.
- Function - In some cases, textures may serve a functional purpose like hiding scratches.
- Cost efficiency - Textured molds can provide visual interest without secondary processing like painting.
With CNC machining, these textures can be machined directly into mold surfaces. This makes them an integrated part of the mold design rather than an afterthought.
Techniques for Creating Textured Molds
There are a few main techniques used to create textured mold surfaces with CNC machining:
Milling/Engraving - Subtractive techniques like milling or engraving remove material to create macro-scale textures. Things like ridges, grooves, and stippling patterns work well.
EDM Texturing - Electrical discharge machining (EDM) uses controlled electrical sparks to erode material. It can be used to make micro-scale textures not possible with conventional milling.
Chemical Texturing - Chemical etchants can be applied to selectively erode areas of the mold surface to create a texture. The process is similar to photoetching or chemical milling.
Laser Texturing - Focused laser energy can also selectively remove material. Lasers allow very fine control for micro-scale patterning.
Media Blasting - Media blasting propels small abrasive particles at high velocity to create a peened surface texture. It gives a matte, coarsely pitted finish.
Combined techniques are often used. EDM or lasers might make the fine details, while engraving handles the larger features. This provides textures with depth and layers.
Design Considerations for Textured Molds
Taking full advantage of textured molds requires designing parts and molds appropriately:
- Draft angles - Textures need draft designed in for demolding. More textured surface area may require higher draft angles.
- Ejection system - Parts may stick more due to increased surface area. An effective ejection system is important.
- Reduced tolerances - Allowable tolerances may need to be widened to account for textured surfaces.
- Parting lines - Any parting line will interrupt the texture, so minimizing or hiding them is best.
- Gate locations - Gate locations should avoid highly textured areas which can hinder flow.
- Mold strength - Textures reduce mold strength, so additional ribbing or thickness may be required.
- Simulation - Flow and cooling simulations help verify textures won't cause issues.
With early planning, molds and parts can be designed to fully leverage custom CNC machined textures.
Example Textured Mold Applications
Here are some examples of molded plastic parts that benefit from textured molds:
Handle Grips - Handles molded with crosshatch knurling or stippling have enhanced grip and comfort.
Electronics Housing - A textured surface can give a high-end branded look while hiding scratches.
Kitchenware - Woodgrain and other textures provide visual interest and branding.
Automotive Trims - Patterned textures match adjacent materials like fabrics for integrated styling.
Medical Grips - Textures tailored to hand anatomy improve medical device usability.
Toys & Games - Imaginative textures align with characters and themes for more engaging play.
The possibilities are nearly endless! Any consumer products with molded plastic parts can likely benefit from exploring custom texture options.
Prototyping Textured Molds with CNC
Low volume production or prototypes can also utilize CNC machined textured molds. Some options include:
- CNC machined aluminum molds - Small production runs below 5000 parts.
- Composite molds - Reinforced epoxy molds for tens to hundreds of parts.
- Direct metal 3D printed molds - Great for early prototyping.
The lower cost and faster lead time of these methods make them ideal for exploration of textures. Feedback can be used to refine textures for higher volume production molds later on.
Closing Thoughts on Texture and CNC
Customizable mold textures enabled by CNC machining open new avenues for plastic product designs. Companies seeking differentiation and unique branding opportunities can use textured molds to their advantage. With careful planning and application of the right CNC techniques, even complex textures are possible. CNC Milling CNC Machining