sweep and restrict

In this scenario we want to restrict a tool path to not cut an edge in a mould by following the mould cavity and "curve up" to the flat surface over the edge. What we aim for is a cut that leaves and enters the edge straight up/down to make the cut as sharp as possible. This is easily made with a sweep command in Rhino. As usual, bring it up to full screen and HD quality!

Profiling with tabs

When making profile cuts in MadCAM there are choices for skin cuts which leaves a thin layer of material in the bottom of the part for holding. But sometimes it's better to use tabs instead of skin cuts, for example if the part need more processing or is flipped for further cutting. Here are two ways to do it. First version

Second version

Region curves vs extruded curve

It's a common thought that the Region curves function is a "hard" boundary that the cutter can't leave. This is a negative assumption. The region curve tells the tool path generator where to cut the model, it doesn't fence the cutter in that area. There is a simple way to make a fenced area with an extruded curve, for example the region curve itself. This will cause the cutter to stay inside the region. Here is a simple example:

Tip! Make a region curve, expand it with a bit more than the cutter radius. Make an extruded curve with the new expanded curve and then use the the smaller curve for the region. Doing it this way the tool path will not climb the wall, it will go directly to the model surface. Here is a bit more sophisticated version, yet simple though:

Knurling and textures

There was a discussion in the MadCAM forum at cnczone.com how to produce textures and as usual it's so much easier to see it visually. Here are my contributions. Knurling The classical line cutting is pretty straight forward, it's just a matter of making the polyline pattern you like and then do it with a Project Curves command. There's a catch though (There will be a check for this in coming releases); you need to cut below the surface to get the lines in the material. You set Stock To Leave to a negative number to do that. But you can't set Stock To Leave to a value lower than the cutter radius! 2 mm cutter, -1 at most. 4 mm cutter, -2 at most and so on. This is only happening on the negative side though. The algorithm behind the path calculation will find edges in the mesh and fall through. BUT there's a simple work around for this. The Project Curves command is only following the polylines with the tool tip and which tool you choose in the cutter dialog doesn't matter for the tool path itself. The only thing that will happen if you choose a bigger cutter is that the simulator will not show the exact result. Select a 4 mm cutter and you can cut to -1.9 with no problem.

Textures When it comes to a 3D surface like a plastic pistol grip, this is how I have done it. There are for sure 10 other ways to do it but this came out very good. * I'm splitting the area of the surface where I want to make the 3D pattern. * Use the ApplyDisplacement command that takes an image and "bumps" the surface. Play with the image itself and the texture settings. I've used an image of gravel. ApplyDisplacement is using the contrast in the image to make the texture within the height you specify in the dialog. A Black and white image with very little shades will make the surface "worse", a softer image will make the surface smoother. * This is not yet a real surface, it's just a visual context. Extract the bumps with MESH->From Nurbs Object, and then apply the mesh on the surface with Mesh->Apply To Surface! * At last, remove the original surface, reselect the working box, make a region and prepare a toolpath.

(And of course, the vid's are available in HD)

5 Axis indexed

This is a small triangle with facets that I made as an example to show 5-axis indexed. This will make the tool tip perpendicular to the surface and the facet will be smooth right away with even with big steps.

Old but nice vid, rear wing model

Old vid showing some Rhino and MadCAM 4 work. These are the sides for a rear wing. The base is taken from measures directly on the car to get a smooth and solid mount. The width is making the wing wider than the coupe and it's resting a bit above the roof.

As usual, I run this demo in a virtual environment and it makes the simulator acting a bit odd. Try it for real!

Toolpath Array

How to make an arrayed toolpath in MadCam. You need to make a Group Repair to reconnect the new paths with the original path.

This clip is available in HD. Maximize the video screen and increase the resolution and you'll have a crisp clear view. As usual, I run this demo in a virtual environment and it makes the simulator acting a bit odd. Try it for real!