Creating Organic Shapes with Mold Textures and CNC Milling(whats bronze made of Miriam)
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Potential Texturing Materials
There are endless options for materials to use for mold texturing. Leaf skeletons, lichen covered sticks and rocks, tree bark, flower petals, fruits and vegetables, woodgrain, seashells, feathers, dried moss, rusty metal, and more can all be used to produce unique organic textures. Anything with an interesting texture can be pressed into clay or silicone to capture the negative space. The texture plates are then 3D scanned, processed in CAM software, and machined from wood, plastic, metal, etc.
Leaf skeletons like ferns and hosta leaves removed of their flesh can create lacy, branched patterns. Pressed flowers, leaves, and grasses make delicate lines and shapes. Bark rubbings give realistic woodgrain textures. Coral and seashells produce wavy, irregular bumps and holes. Patinas created by rusting metal through saltwater or ammonia exposure can be captured to simulate aged, worn surfaces. Liverwort lichen provides tiny granular spots when pressed. The options are truly endless for discovering new texture samples all around in nature.
Pressing and Scanning Texture Samples
There are a couple options for capturing mold textures. The first is pressing samples into platinum-cure silicone rubber. This flexible mold material picks up fine details in textures and allows for creating stamps that can continue being reused. Samples should be pressed into the silicone, allowed to cure, and cut out to create stamps.
Another option is pressing samples into oil-based clay. The clay holds very crisp imprints of textures without distorting delicate details. Once imprinted, the clay can be baked to harden it before 3D scanning. Sculpey polymer clay works well for capturing textures at the small scale needed for high resolution 3D scans.
No matter which material is used, it’s important to get a very clear impression of the texture the first time.Blurry or shallow imprints will not scan well or mill precisely. Applying adequate pressure while pressing the sample into the material is key.
Once texture plates are created, they need to be scanned to convert into digital 3D models for CAM software. Photogrammetry using a digital camera with macro lens can capture high resolution details by taking photos at multiple angles and running them through photogrammetry software like Metashape or RealityCapture. For larger plates, a 3D scanner like a desktop CNC scanner produces clean scans. The resulting 3D model retains all the tiny pits, crevices, and articulations of the original texture sample.
Preparing Scans for CNC Toolpaths
Before the texture 3D model scan can be machined, it needs some preparation in CAM software. The model first needs to be trimmed to remove any edge artifacts from the scanning process. It’s also important to ensure the scan is water-tight and free of holes so it will machine smoothly. Depending on how the scan was captured and processed, there may be some mesh repair required.
Next, the scan needs to be scaled to the desired size for the project. Enlarging or shrinking the textured shape while retaining the high resolution detail is simple. The original texture sample likely measures just a few inches, but we can scale it up to produce a textured panel covering several feet.
With the scan repaired, scaled, and ready for machining, it’s time to generate toolpaths. Most CAM software allows you to select horizontal, parallel, or radial toolpaths to machine the texture evenly. 3D contouring can follow the texture topology for molded 3D surfaces. Optimal chip load, stepover percentage, feed rates, and other parameters may need refined based on the material and texture complexity.
Machining Organic Textures
Once the toolpaths are programmed, the textured model is ready to be physically machined. First, a base material needs selected. This is the blank material that will be milled into the finished textured piece. Wood, plastic, foam, metal, and composites will all work. Harder materials hold crisp details best while softer materials allow for more organic variations.
The base material must be mounted securely in the machine. It also needs to be faced and surfaced flat and level so the texture depth mills evenly across the entire model. With the material prepped and zeroed in the machine, the texturing toolpath program can then be run. Typical texture depths range from .1” to .5” but can be adjusted as desired. Deeper textures require smaller stepover percentages to avoid excessive tool deflection and shadows.
When machining is complete, the result is a panel, object, mold, stamp, or other creation covered in the natural texture captured from the original sample. The fine details of the texture are translated to the machined surface, creating an organic shape perfect for decorative panels, furniture accents, architectural millwork, molds for castings, and any application needing a one-of-a-kind natural design.
Post-Processing Options
After machining, some post-processing may enhance the molded texture even further. Sandblasting can accentuate fine pits and crevices. Staining or liming can bring out different grains in wood textures. Painting and then sanding to reveal raised details works well too. Distressing, burning, and artificially weathering the piece can make textures look aged and historic. Clear coating can be applied to seal and protect the finish.
The opportunities are unlimited for the types of natural molds and textures that can be captured through this process. let your imagination wander outdoors and discover texture samples everywhere in forests, gardens, beaches, and other landscapes. With a simple press into clay or silicone, creative scanned textures can be produced to add artistic natural designs to CNC machined projects. CNC Milling CNC Machining