Mold Textures in CNC Machining(difference between cold rolled and hot rolled steel Neil)
- source:NEWRGY CNC Machining
Mold textures serve several important functions:
Visual Effects - Textures can impart visually appealing effects to molded plastic surfaces, such as leather, wood, or fabric-like finishes. Subtle textures can also help hide minor surface defects.
Grip and Feel - Textured surfaces provide tactile grip and an enhanced ergonomic feel for hand-held products like toothbrushes, razors, and kitchen tools. Fine textures give a smooth luxurious feel to surfaces.
Strength and Durability - Rougher textures can improve the mechanical locking strength and durability of inserts molded into plastic housings. Textures allow molded features to withstand higher pull-out and torque loads.
Fluid Drainage - Channels, perforations, and grooves in textured surfaces facilitate drainage of water, grease, and other fluids. This improves usage and cleaning abilities.
Light Diffusion - Optical light scattering properties of textures are utilized to diffuse LED illumination and hide hot spots in molded light covers and housings.
With CNC milling and machining centers, mold textures can be produced using a variety of techniques:
- Engraving via small end mills creates fine detailing and precision patterning effects. Small end mills are available down to micro diameters for high resolution capability.
- Ball end mills generate free-flowing curved contours and organic artisan-style textures using specialized CAM programming. Their rounded profiles prevent hard sharp corners.
- Chatter texturing utilizes lateral milling oscillations to generate wave-like disturbances on a surface. Different vibration patterns and tool geometries create unique appearances.
- EDM texturing employs electrical sparks to erode very fine and complex textures resembling laser etching but on conductive materials like steel molds. No tool contact occurs.
- Media blasting projects fine abrasive particles at high speeds to produce uniformly rough textures through controlled material removal. Masking defines patterns.
- Chemical texturing selectively etches the mold surface to desired depth variations using photoresists and acid/alkaline etchants.
- Laser texturing directly scans high peak power laser beams over the mold surface according to digital motifs to melt, ablate, and rough up localized areas.
For all texturing methods, the CAD model needs proper surface preparation to define all required textures and convert them into toolpaths for the CNC. MasterCAM, SolidWorks CAM, and other CAD/CAM software have advanced 3D surfacing abilities to program even complex free-form mold textures.
Standard end mills and ball end mills are commonly used, but specialized cutters are available. Micro-ball end mills for fine detail work, chatter tools with oscillating heads, tapered conical tools for draft angles, and other profile cutters can generate unique topographies unattainable with standard tooling. Tool selection and parameters must suit the material, finish requirements, and product longevity needs.
On softer aluminum or epoxy molds, very light machining passes are needed to avoid excessive tool burial. Hardened steel molds can accept more aggressive cutting but require positive chip clearance. High speed machining with small cut depths maximizes texture resolution. Mold polishing may follow texturing to smooth any sharp peaks or troughs.
Proper fixturing, workholding, and machine setup help achieve dimensional accuracy and repeatability for textured CNC mold work. The mold must be securely mounted to avoid vibration or deflection during machining. Precise process control maintains consistency between molded parts.
With CNC's innate precision and flexibility, mold texturing possibilities are endless. Brand logos, custom labels, complex 3D topologies, micro patterning, and even simulated carbon fiber effects can be machined directly into mold surfaces. This allows plastic parts to exhibit truly unique appearances mirroring the molded textures. By leveraging CNC's capabilities, product designers can introduce new aesthetics, functionality, and brand identity into molded consumer products. CNC Milling CNC Machining