Machining in 4 axis: Helmet

posted in: Machining Projects | 5

After all the work on the design and construction of the 4th axis is the time to try and learn to use it. I found online a model in stl that I liked, and modify it for machining: the helmet of a Stormtrooper from Star Wars. Yes, I’m a fan of Star Wars, lol.

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Well, get to work. I have programmed 4-axis machining in Vectric Aspire. If anyone is interested in how to make this work, I’ll make a tutorial on how 4-axis machining in Vectric Aspire.

It is important to have well-defined starting material, because it will be necessary to model it Vectri Aspire can do the corresponding slab. In my case I have prepared a rectangular piece of pine 45x45x150mm. The workpiece I have scaled to fit within a cylinder of Ø38mm and no more than 50mm long, so I’ll have plenty of material. Being the first time I do not want surprises.

As seen in previous posts, the 4th axis was almost entirely finished, so I have placed it in the bed of the mill, and after the machine origin touches define the origin of the piece. As Vectric Aspire configures to machine a revolution part 4 axis, the workpiece in X, Y and Z are located on the axis of revolution, and the upper face of the cylinder. For practical purposes, I put the tip of my tool Y and Z on the axis, and then I decide where X is about to get the piece within the length of the billet of wood.
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In this picture you see the 4th axis positioned on the bed, and with the tool in position X = 0 Y = 0 Z = 50. Believe it, I have not yet given to run the code, it took me a few hours to learn how to configure it right, the directions of rotation and tool change. The G code generated by Vectric Aspire is compatible only with a fourth axis formatted for Mach3: Mach2/3-WrapY2A ATC (mm) Well after researching (although I could be wrong) is the only code that I have in mind that the fourth axis is A. However, I load a set of instructions G that deconfigure my LinuxCNC operation, are the G’s in the program header. So I loaded the header of other programs already operating me, and I modified the tool changes, and some things for my own comfort. It is always interesting to review the code well if we do not want surprises, for example, before the change of tool, place the tool coordinates where disassemble it enough to comfortably space.

Once the code is correct, it is time to start machining.

In Vectric Aspire, I configured machining three subphases:

A first rough, it will be to make a rectangular volume of a cylinder 45x45x150 Ø39×150. Vectric Aspire purposely has a program for this operation:

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The following video is going to look like roughing is performed, it will machine the corners to get a cylindrical surface that previously we have configured in dimensions:

Once the first rough, starts the second without tool change is the same tool. This will start to be the final form. Not much more to tell.

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As you can see in the video, the rotation is perfectly rhythmic, but looks set to stumble, but is only a matter of speed and trajectory changes mixed with accelerations. Perhaps this can be corrected, but not important.

Finishing second roughing, the tool is placed in a comfortable position for mounting the spherical cutter Ø4, 5mm. And we continue machining. This phase I configured such that the cutter traverses the spiral-shaped part.

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The images and video may be seen what was the error of this piece. The material is a piece of pine, and the tool was perhaps too revved and a slow feed. This has caused the wood to overheat. This surely has made the resin timber still has, more or less melted, so that the piece has been with a texture like wet, besides being tacky. Obviously the finish is bad, poorly defined, but this was still a test, which I have shown my 4th axis works perfectly. Only I have to learn to use it well, which I have done with this example amply. In addition, the piece was relatively small, and knew that with a spherical Ø4.5mm could not get much resolution. Still, this was the result:

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For what I wanted, it is acceptable. Now I know how to fix this machining defects, for example, by selecting a suitable material, changing cutting conditions, and choosing the right tools. Another option to get more definition, use a cutter to engraving a second finishing phase, which will take more time, but with a sharp point will be able to draw much better detail.

So next, proves something perhaps bigger, and attending to these details. Any suggestions for the model? Contact me!

5 Responses

    • ostervi

      Hi! I had in mind make this tutorial. I will do it soon, and I will upload to this web, so check it often, or subscribe to this web.

  1. vicmon46

    Hola, tan solo dos apreciaciones.Primera, procura usar madera poco veteada, en este caso se ve que es de pino y no del mejor (por desgracia es lo mas asequible).Y segunda, que sea lo mas seca posible, los problemas que has tenido han sido por calentamiento y como está fresca y con mucha veta resinosa (las oscuras), expulsa la resina y emboza la fresa.Por lo demás, adelante con los tutoriales.Saludos.