[andrewreed1]

Hi all,


I am involved with Scale RC aircraft and have recently come into possession of a Roland MDX-15 Bench top 3D mill. I intend on using it for aluminum to cut parts and also to cut master molds for plastic injection. But I have never run a mill myself, even though I have some experience with 3d CAD. The CAD software is Rhinoceros 3.0, in case you were wondering.

BTW, I already have a 3d model of a simple part I want to cut, but have no idea exactly what to do next. I do have some pieces of aluminum stock to try, and will get some wood as well to start out with... I am just clueless where to start... How do I mount the stock? What cutter do I use? So many questions, so little time!

Any help or info you can give is greatly appreciated!

[CNCBoss]

It is hard to answer your question without specific's on what you are going to cut. You have to realise that machining is not something you learn over night. It has taken me 25 years to accrue the knowledge I have of machining.
How to hold your part? Depends on the part and the geometry you are machining. You can post a file of the part you are trying to make and then others can comment on "how" to do it. Most of the time you are looking at a vise to hold your work.
I don't want to discourage you but there is a LOT to learn about machining! Stick with it.

[HelicopterJohn]

Hi Andrew,

I sent you a PM.

John

[CNCBoss]

Nice page John. I believe you are the best person to help Andrew on his way.
Have a fine day gentlemen!

[andrewreed1]

BTW, I submitted a similar post in the benchtop forum...
http://www.cnczone.com/forums/bencht...ml#post1054201

That thread is probably the best place to continue this discussion, since I uploaded a screenshot of the part I am working on. Although the part is related to this forum as well, as it is the flybar locking tool that I am going to be machining. It may be a bit overkill for the task, but I am trying to work out some ideas for blade pitch adjustments anyway, and figure making parts/tools and jigs for this is a great way to learn the best methods to cut parts on the MDX-15.

[skray775]

After you draw up the cad file you need to produce Gcode to run the machine with.

I would suggest experimenting cutting foam or something soft to start with.

Your tool selections depend on the type of cuts you need to make for your part. Part holding can be as big of a challenge as making the part itself. Vise's clamps, bolts.... all can be used you just need to think through your projects and planned cuts.

[andrewreed1]

Part holding can be as big of a challenge as making the part itself. Vise's clamps, bolts.... all can be used you just need to think through your projects and planned cuts.

So I have been finding out. As mentioned previously, for years I was exposed to PCB manufacturing, where pinning was used. The router (Gcode) programs contained a pinning drill tool as the first set of instructions. The operator would run the program, which would drill holes in MDF backup material. The MDF was itself, pinned to the work surface but was the sacrificial spacer. Pins were then driven into the MDF and the panels to be routed were placed onto the pins, sometimes two or three panels stacked together. The remaining tools were then run on the machine. With known material thicknesses, feeds and speeds, cutter deflection was compensated for by telling the CAM software the cutter diameter was smaller than it was, typically it was a reduction in diameter of about .004". But PCB milling/routing is basically 2D cutting, rarely if ever was there any 2.5D or 3D going on. Plus, we were typically cutting FR4 material (fiberglass-based), and the milling machines had pressure feet and vacuum heads.

At one shop I worked at, the panels were pinned and the boards werekept in the panels via supports (break tabs), with .006" gaps. At another shop, there were no tabs, as the boards were also pinned to the MDF and the program simply plunged just off the edge of the board, cutting a complete path around the entire board and ending just beyond the beginning plunge.

If only 3D machining were so simple.