[Zman2015]

Hello everyone this will be my first build I am completely new to the CNC world and would like to take my woodworking skill to the next level!

I have been reading and researching online for the a while now trying to come up with the best plan/machine for what I want to accomplish primary will be for hard woods Oak,Walnut and some Aluminum if able to do 20mm that would be great. I am not looking for a machine to be quick to push out product.

4 Axis Machinesize no bigger than 36x48 or 36x36

Linear rails: HiwinHGR25R

ACME Ball screw 1616 or 2020?

Nema 34 906 oz. motor or NEMA 24 steppers - 567 oz-in bipolar rating (from PDJ)?

I plan on using a spindle. As far and the frame I would like to use rectangle steel A513/A500 3” x 1.5” x 3.16” thickness but Iknow the steel could warp so the option is 80/20 extruded aluminum. Looking for a solid/ ridged machine.

Also my work has a CNC solder paste machine for PCB boards with the ball screw at the top connected through the side gantry. I know the CNC isn’t made for heave work but to be fast, can the design work for whatI want to accomplish or does the ball screws need to be at the bottom of the Yaxis?

I still have a lot to learn any suggestions I would appreciate it?

Thank for the help!!!!

[wizard]

Hello everyone this will be my first build I am completely new to the CNC world and would like to take my woodworking skill to the next level!

I have been reading and researching online for the a while now trying to come up with the best plan/machine for what I want to accomplish primary will be for hard woods Oak,Walnut and some Aluminum if able to do 20mm that would be great. I am not looking for a machine to be quick to push out product.

4 Axis Machinesize no bigger than 36x48 or 36x36

That is a reasonable size to start with. As for 4th axis what exactly are you thinking about here?

Linear rails: HiwinHGR25R

ACME Ball screw 1616 or 2020?

Nema 34 906 oz. motor or NEMA 24 steppers - 567 oz-in bipolar rating (from PDJ)?

I plan on using a spindle. As far and the frame I would like to use rectangle steel A513/A500 3” x 1.5” x 3.16” thickness but Iknow the steel could warp so the option is 80/20 extruded aluminum. Looking for a solid/ ridged machine.

Even for this smallish machine the 3 x 1.5 tubing could be a bit small depending upon where you are using it and what your expectations are for the quality of the cutting.

I'm not sure what you are referring to as far as warping goes. If you weld the frame up you need to consider stress relieving the frame. However don't go thinking that aluminum T-Slot extrusions automatically secure you from a machine going out of alignment. I'd strongly suggest leaning towards steel as it is overall a cheaper way to build a frame. Also you can, id some thought is put into it, designs a steel tubing machine that doesn't require welding thus minimizing building in stress in the machine.

Also my work has a CNC solder paste machine for PCB boards with the ball screw at the top connected through the side gantry. I know the CNC isn’t made for heave work but to be fast, can the design work for whatI want to accomplish or does the ball screws need to be at the bottom of the Yaxis?

I'm not sure I'm following the question! In any event, in an ideal world the lead screw runs between the Y axis linear bearings. There are lot of was to do this differently though.

I still have a lot to learn any suggestions I would appreciate it?

Thank for the help!!!!

Suggestions are easy:
1. Read the stickies.
2. See if you can spend some time in a machine shop and look at how milling machines are built. You can't expect a machine built out of steel tubing to achieve the same results as a huge cast iron machine but the arraignment of components would be very similar. Most mills will have the lead screw centered between the ways for each axis. A common error to this rule is the Z axis on knee mills.
3. Even if you build most of your machine out of aluminum T-Slots I still suggest a steel beam for the Y axis. The gantry is usually weak area on DIY builds and is difficult to address after the fact if a flimsy design is used with the first go around. Depending upon your Y axis clearance you would be looking at a square tube beam that is at least 5" square, The higher the Y axis the larger your beam. Also there is an issue here with component fitting. You need a surface wide enough to mount your lead screw, and the two linear bearings.
4. With respect to item 3 above, Hiwin HGR25R are rather large rails, the bearing cars can range in width from around 1.9 to 2.8 inches in width. That can be tight squeeze on 5" square beam. This doesn't even include consideration for where your lead screw goes. Further your 3 x 1.5 inch tubing couldn't properly support a rail of this size on the rest to the machine. I'd suggest a smaller series rail or a far beefier machine, otherwise your investment in rails would be wasted.
5. The clearance under the gantry beam has a big impact on the torque seen by the machine when it is cutting materials. The higher this clearance the beefier you machine needs to be. Beefy being stiff in this case.
6. You didn't mention if this is a moving gantry design or a moving table design. The machine is on the borderline of being to big to really get a moving table design to fit into the work place. However realize that a moving table design can be far stiffer and likely easier to build. If this was a smaller machine I would suggest going the moving table route to get better results with aluminum machining. Right now you are on the borderline of feasibility. So just something to consider.
7. Pictures are worth a thousand words.
8. Decide if portability or transportability is important to you. If it isn't build a heavy machine as opposed to a featherweight. The reason is simple weight helps with vibration and if in the right place will enhance stiffness. The stiffer the machine the higher the cut quality.
9. Don't get too excited about controls until you have a design nailed down.

[ger21]

25mm Hiwins are much larger than you need. 20mm 's are still way overkill, and will support thousands of pounds.


Acme and ballscrews are two different things.

I'd use 2010 ballscrews and these motors.
High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. Stepper Motor | Stepper Motor Driver | CNC Router | Laser Machine | 3D Prin

[Zman2015]

Great advice!! I plan on having a moving gantry attached is a picture of the machine at work of what I was talking about the ball screw through the gantry. The frame on both sides are a square "outside shape" with the liner rails on top.

I was thinking but I am sure it is overkill to have a pair of linear rails on each side of the Y axis at the top and bottom? I have never seen this before. Would you gain stability? My basic design in theory to have a complete "box" steel frame with rails on top and bottom with a 20mm alum plate connecting the two rails together and the gantry closer to the top screwed onto the plates, the stepper motor would than be portioned/ connected to the plate allowing it to move the gantry. If this makes sense?

Z axis I was looking for about 8"

Thanks again


Attachment 348124

[CNCArtD]

vxb has linear rails and ball screws available now here.