To make explanations easier I have rerendered the design with the bed and I have colour coded various sections of the design.
Frame = Grey
X Carriage (Gantry) = Red
Y Carriage = Yellow
Z Carriage = Blue
Spindle (Router) = Green
Originally Posted by
FandZ
I'm not sure if I'm fully grasping your design, but the way I'm seeing it, your spindle will be dropping down from the middle correct? I'm not seeing it upside down? If this is right side up, I'm curious why you have so much room above your z axis?
You are not seeing it upside down. The image shows the machine from above.
I think I see where the confusion is coming from. What I had drawn was just the main workings of the router. As can be seen from the new image, it will all be mounted 12-18in above the bed. The spindle (green) will be mounted on the bottom plate of the Z axis (blue) and the body extends up through a hole in the center of the Y carriage (yellow). The bit will extend down through the hole in the bottom of the Z carriage.
Originally Posted by
FandZ
It looks to me you'll only have a z travel of maybe 2 inches. That would limit your choices of tooling bits a good bit. No pun intended :P
I have a full 12in of Z travel. As the router is mounted on the bottom plate and moves through the center of the Y carriage, I can move the Z carriage all the way up and down. Of course I don't need this much travel most of the time, so will work much closer to the Y carriage.
Originally Posted by
FandZ
I see you are considering driving the Y axis from one side. Even with a cable support system, you'll be robbing your steppers of power. It can work, but why start with an inferior way of driving it? Steppers are cheap. My suggestion would be to either drive it from the middle (not possible with this current design) or drive it from both sides (the best option for all builds). You could also drive it from the middle useing belts but why waste stepper/servo power...
Originally I was going to do just that, but after reading this forum for a month or two I rethought the system. From what I read, it seems that two motors on the same axis is just asking for trouble. A missed step on one motor will introduce forced racking.
As far as I have read (both here and elsewhere), the cable system is simple and will transfer power from one end of the gantry to the other with very little loss.
Originally Posted by
FandZ
Lastly, it's a closed box. Which will limit the length of your stock. Consider opening the front and the back.
The frame as was drawn will be 400mm above the bed so there is plenty of room to move materials in and out. This can be seen in the new image.
Originally Posted by
FandZ
My last question would be, how do you plan to make this and out of what? I'm not talking about the rails and such but am really asking about the framing and supports. Will you be wielding it together or bolting?
The main frame (grey) is probably going to be welded steel.
The gantry will be 5mm aluminium bolted together
The Y carriage is basically a single peice of 10mm aluminium with bits bolted on.
The Z carriage is a 10mm plat on the bottom and a 5mm on the top.