T-Slot cutting, Anyone done it?

I am planning on ordering an X-Carve in a couple days. Before I do, I am curious to make sure that what I want to do can be done. I have been having someone else cut these mazes out of 3/4" MDF, but I want to bring it in house. Has anyone done any t-slot cutting with their X-Carve? I planned on using a straight bit to cut the straight slots and outside, and then loading a t-slot cutter, re touching off the z, and then running it thru all the slots.

https://dl.dropboxusercontent.com/u/25842852/forum%20post%20photos/2015-08-17%2015.14.28.jpg

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The X-Carve can do it, but you are going to need a really precise method of setting your work zero, since the second cut with the t slot cutter must exactly follow the first straight cutter.

You will also really need a heavy duty spindle since the t-slot cut must be done in one pass. I highly recommend the Dewalt dwp611.

I was going to buy the full loaded maxed out assembly with highest quality and largest available on all the options.

Once the machine is homed with the limit switches, does it not repeat if you run multiple programs on the same material without moving it?

You will also need a CAM program that you can control the tool paths with. In the example you showed I see one entry point and one exit point. You will have to make sure that once you start the slot that the cutter stays in the slot until it has completed all of the maze pathways. You don’t want it to get to a dead end and lift the cutter to move to the next part of the cut.
I would be talking with the person that is doing the work now and see how he or she is doing it if they will share with you.

Dave

That is a really good point. If I told Vcarve to do a profile cut along that vector it would certainly try to reposition the bit many times.

You could do it in three layers:

  1. a solid circle base
  2. a middle layer with a wider maze
  3. a top layer with a thinner maze.

(This is on my to-do list.)

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That may be the safest way to do it because I was just looking at the example shown and there are a ton of dead ends that would mean backing up to a junction and then off in another direction till you hit another dead end.
this would not be easy.

Dave

If you do not do it in three layers another possible method would be to let the X-carve cut the straight cut. Then just use a router with a t-slot bit to follow the straight cut.

In case it helps, I should say that I program and operate a 10’ x 5’ Andi CNC router using Alphacam as one of my jobs at my day job. Since I can’t do side work there, that is why I’m buying the x carve for my owne shop.

I was looking at buying v carve pro with the x carve. Since I have no experience with this software yet, do you think it will be impossible to make this work?

The straight cut will work fine but vCarve pro cannot generate a tool path for the wider t-slot with out lifting the bit and breaking something.

2 points…1st…if you set grbl up to keep the motors powered with the nema 23 steppers, there is little chance of moving the head while changing bits.

2nd…you could generate the code in pieces, ensuring you are only going over the previous cuts then removing any z-axis movement with a text editor…it would be time consuming to set up, but once it was done, you wouldn’t have to do it again.

Doable, but time consuming.

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Editing G code is not a problem. I do it on a regular basis, but programming from scratch without CAM for all the paths would be horribly time consuming.

If I understand correctly, I can use any CAM to generate the G code to operate the x carve? If this is the case, does the x carve follow standard G and M codes for movements?

http://www.shapeoko.com/wiki/index.php/G-Code

Check this out for supported g-code.

Thanks. That is a great list, and appears to follow all the standards I am use to working with on all the CNC machines I am use to.

I suppose to get around the problem, I could divide up this single part into two layers of 3/8" material, router one thru with the smaller width slot, router another piece of material with a wider slot, and then glue/nail/screw them together, thus eliminating the need for changing the tools and t-slot cutting, I would just be making two individual parts and assembling.

That would work…don’t be concerned about changing bits in the middle of a job, it truly is easy. If you have the Nema 23 motors changing the setting to $1=255 keeps the motors powered and changing the bits is easy with almost no chance of moving the spindle. You would really have to pull hard to move it.

It’s not so much the XCarve as grbl that you care about for this - take a look at https://github.com/grbl/grbl/wiki. (grbl is the thing that’s going to translate gcode to commands to the gshield board that actually drives the steppers).

You might consider making it with a 1/4" base and 1/2" piece that is glued to the base. Cut the wide slot into the top of the 1/2" piece and then cut the smaller slot through to the bottom of the 1/2" piece. I think you could do this without changing bits.

Glue-up would be the next problem. You could apply glue sparingly to the 1/2" piece to minimize cleanup.

Daryl

I think a 2 layered approach would be the best option for this. You could accomplish this relatively easily by either leaving the two pieces square to allow for easier alignment during the glue up then but then to the round shape after they are dry. Another option would be to cut them to shape before milling the groves then mill a few holes for dowels that would be used as alignment pins when gluing them together.

Multi layer, dowels and glue would be my recommendation also. Technically simpler and would give the option for cheaper materials “inside” and quality top surface if required.

Cheers

Ian