Manufacturing Molded Textures with CNC Machining(mig vs tig welding Penny)
- source:DAHLER CNC Machining
Understanding Mold Textures
Textures give interest and visual appeal to surfaces through the use of repeating 3D patterns. In molds and castings, texture is imparted from the mold surface onto the cast part. Common textures include leather, stone, wood grain, linen, diamond plate, etc. The texture gives the appearance and feel of a natural material without having to use that actual material.
On molded or cast parts, texture performs a dual role. It gives an aesthetic, high quality finish to the part while also helping to hide any surface defects in the casting or injection molding process. The textured surface helps mask any minor imperfections.
Key Benefits of CNC Molded Textures
There are several advantages to using CNC machining to create molded textures:
- Consistent, repeating patterns: CNC programming allows for extremely consistent, uniform texture patterns across the entire surface since the same tool motion is exactly repeated by the machine.
- Faster production: Textures can be machined much faster than hand sculpting or engraving a texture. Changes are fast too since you simply modify the CNC program.
- Cost effective: No need for secondary operations to add texture. Reduces labor, tooling costs.
- Design flexibility: CNC allows creating virtually any texture pattern that can be digitally modeled.
- Tool steel durability: Texture tools steel used in CNC is extremely durable and long lasting.
Overall, CNC molded textures bridge the gap between mass production efficiency and individual hand crafted detail. Parts get unique surface interest economically.
Designing and Programming CNC Molded Textures
There are two main methods for programming molded CNC textures:
1. 3D Surface Modeling
- Texture is modeled into the 3D CAD design file and surfaced onto the solid model.
- CNC tool simply follows the CAD design surface.
- Allows very complex custom textures.
- More involved design time required.
2. Direct CNC Programming
- Texture tool motion is directly programmed in CNC code without a CAD model.
- Simple repeating patterns like diamond plate.
- Very fast setup but less complex possible.
Whichever method is used, the CNC program essentially defines a series of repeating lines, contours, and/or arcs for the tip of the texture tool to follow across the work surface. The right texture tool is then selected to cut this path and leave behind a molded form.
For 3D surface texturing, CAD/CAM software converts the textured CAD model into precision machine code that guides the CNC to match the desired shape. This enables emulating textures seen in the real world.
Popular Molded Texture Patterns
Some of the most common molded texture patterns machined into parts include:
- Diamond Plate: Intersecting raised diagonal lines forming an angular pattern. Used to provide grip and slid resistance.
- Leather: Pebbling grain giving a natural leather look. Different pebble sizes possible.
- Wood Grain: Long sweeping lines with dark/light contrast mimicking real wood.
- Linen: A fine close-knit cloth like texture. Provides a dramatic contrast to smooth surfaces.
- Sand: Coarser irregular bumps suggesting sandy or gritty texture. Used on handles and grips.
- Dot Peen: Uniform dimples in consistent rows. Gives a machinelike appearance.
- Custom Patterns: Unique textures matching a specific product theme.
The CAD models or CNC programs for these textures can be saved and reused on future projects, fully digitizing the texturing process.
Specialized Tooling for Molded CNC Textures
Cutting and forming textures requires using specialized CNC tooling. This includes:
- Ball Nose End Mills: hemispherical tipped cutter for 3D contouring and fine details
- Engraving Cutters: Hooked tip tools that scoop out material for bold textures
- Denibbing Tools: Spherical cutters with serrated teeth to rough up surfaces
- Chamfering Tools: Beveled cutters to create angled sides on textures
- Thread Milling Tools: For cutting crisp, defined threaded textures
- Fly Cutters: Single point rotary cutters often used for patterned lines
The end geometry, stepover, feed rates, and cut depths for these tools are all optimized for getting good chip load and clean definition of the textures. Tool paths also avoid excessive tool wear and deflection.
Common Metals for Molded CNC Textures
Texturing effects can be machined into most engineering materials. Here are some typical applications:
- Aluminum: Very fast machining. Well suited for medium to coarse textures.
- Brass: Easily textured but higher tool wear. Excellent fine detailed textures.
- Steel: More tool wear but can impart deepest, sharpest textures. Great durability.
- Titanium: Challenging material but important for medical parts. Needs rigid machining.
- Plastics: Easily textured for prototypes and injection molds. Low tool wear.
Molded textures are also added to molds for die casting, plastic injection molding, blow molding, and other processes. The textured mold surface imparts the negative pattern onto the cast or molded parts. This is an efficient means of mass production.
Advanced Molded Texture Techniques
For more advanced textures, CNC programming can manipulate the tool motion to create extra detailed effects. This includes:
- Varying texture pattern density across a surface. Sparse here, dense there.
- Combining multiple tool sizes in one program. Large main texture with small micro-textures overlaying.
- Transitioning from one texture to another across the form.
- Using contour ramping to smoothly transition texture depths.
- Adding skewing, stretching, or compressing effects to alter the alignments.
Many neat options are possible to take CNC texturing to the next level.
The automated nature of CNC machining makes it an ideal process for manufacturing high quality molded and embossed textures on parts and products. Consistent, intricate textures that would be impossible to create manually can be programmed into the CNC tool paths. This unlocks new possibilities for decorative and functional textured surfaces to enhance industrial design. Parts benefit from uniquely textured and contoured surfaces at fast production speeds. CNC Milling CNC Machining