Acrylic 1st profile cut

[microreefsaquariums]

Quick question?

I have the AR-16 Elite and I did a complete home on XYZ.  Then I brought over the working piece 8X, 5.5Y using half inch acrylic thickness to the machine.  CAD showed profile cut simple rectangle, 4X, 2Y.

I placed the workpiece on the spoil boards and did another XY zero making sure to bring down my tool where it would show that starting point.  Did the Z touch off perfecting then with 5 passes my 1/4 inch end mill plastic bit did a fantastic flawless cut.

However, the rectangle was not flush as the CAD program showed.  Where did I go wrong?  I feel that somewhere on Zeroing out the X,Y,Z has been an error

or miscalculation. I have gone back to CAD and the values there are consistent so, something is happening on my working area machine bed.

Can anyone lead me into the catching the error so I can have a perfect cut , this zeroing out on the workpiece on the machine is not going to plan since the cut came off not centered from CAD.

Thanks,

Mike G

User error, entered wrong values for work piece problem solved!

Attachments:

[microreefsaquariums]

I homed the XYZ again to the machine, and then carefully jogged the tool bit to the desired work area on the spoil boards. Once there, I hit the XY home key on the controller, then the puck on the Z. My second piece that I cut had much better borders than the first. I am most likely sure that I was off and not careful the first time I homed the XY on the work material.

Here are some pics of my 1st and 2nd attempt and the layout of the eurobrace I need to cut perfectly for my project.

Attachments:

[dadealeus]

Sept 3, 2022 11:36:09 GMT -5 microreefsaquariums said:

Quick question?

Hey Mike,

I'm happy to try to help, but I've read your post a couple of times and I'm still not understanding what you're trying to say. From what I'm reading, I'm gathering that you're trying to center the cutout on your work-piece to essentially create something that sort of looks like an acrylic picture frame and the problem you are having is that the cutout from the center of the workpiece is not centered - so you end up getting uneven edge widths on the "picture frame".

Is that correct?

If so, I believe you're just having an issue setting your stock point accurately and I have a couple of questions:

1) What CAD software are you using? Vectric? Fusion 360? Something else?

2) Where are you setting your stock zero position in your CAD software?

For a job like this, I would recommend that you set your stock point to the center of your job (in the CAD program), then draw a physical 'X' across your work-piece from corner to corner with a pencil. Then, using a v-bit for setup (because it has a nice, small point), move the tip of the v-bit to the center of your drawn 'X' and zero the XY out from there and then zero out the Z axis an inch and a half or so over the top of your workpiece.

This will allow you to run an "air cut" that should be calibrated on the XY axis, but not actually cut into the material (because you set the Z-axis intentionally high). This will allow you to visually inspect where it's going to cut without actually cutting your workpiece until you're satisfied it will be done correctly.

Once you verify everything is calibrated correctly, just zero out the Z-axis using your puck as you have been and re-run the same program and you should be good to go.

[microreefsaquariums]

Dadealeus, that is brilliant advice about doing the crosshair and starting from the center of the workpiece, that makes total sense and would give me a perfect starting point! What I did was, use the bottom left starting point with my 1/4 inch EndMill, as I drove it down to the corner of the workpiece I placed two small pieces of acrylic on the two sides of that starting point, like creating a right angle, then I jogged the bit until it touched each side of the acrylic block, I could dial it down to the hair as the two small pieces of acrylic could move and then go back into place if I bumped them too hard, it wasn't that hard to do. But your way sounds even more down to the wire, with X marking the spot and using the V bit to touch down on that value. Either way I got much more impressive cuts having fixed the correct values for the work piece. I am using VcarvePro and since I have you on topic, how does the Anchor Points work in the CAD section? I kept trying to create 3.25 for X and Y so I can have that border across the perimeter of what I was cutting out but it got messed up and then I just eyeballed what looked good and then did subtraction from the values to the actual dimensions of the workpiece, still off by a little but doable. I would like more precision moving forward for less work on may end. Thanks

[dadealeus]

Sept 4, 2022 19:24:44 GMT -5 microreefsaquariums said:

Dadealeus, that is brilliant advice about doing the crosshair and starting from the center of the workpiece, that makes total sense and would give me a perfect starting point! What I did was, use the bottom left starting point with my 1/4 inch EndMill, as I drove it down to the corner of the workpiece I placed two small pieces of acrylic on the two sides of that starting point, like creating a right angle, then I jogged the bit until it touched each side of the acrylic block, I could dial it down to the hair as the two small pieces of acrylic could move and then go back into place if I bumped them too hard, it wasn't that hard to do. But your way sounds even more down to the wire, with X marking the spot and using the V bit to touch down on that value. Either way I got much more impressive cuts having fixed the correct values for the work piece. I am using VcarvePro and since I have you on topic, how does the Anchor Points work in the CAD section? I kept trying to create 3.25 for X and Y so I can have that border across the perimeter of what I was cutting out but it got messed up and then I just eyeballed what looked good and then did subtraction from the values to the actual dimensions of the workpiece, still off by a little but doable. I would like more precision moving forward for less work on may end. Thanks

Happy to share, but I certainly can't claim credit for that idea; just something I picked up from people with a lot more experience than me! Just trying to pay it forward, I guess.

As to your question about the anchor points - I'm no expert in VCarve/Aspire, but I'll do my best to help. I believe the best tool to most easily accomplish what you're trying to do is the "offset" tool. The easiest way I've found to do it would be this:

1) Create a new file and make the size of the job the exact size of the piece of acrylic you're working with. Let's use the example of 6" wide, 4" tall, 1" thick. Set the "XY Datum Position" to the center and click 'ok'. You should now have your white box the size of the parameters you entered.

2) Click the "Draw Rectangle" tool and then click somewhere in the lower left of the white work area (the anchor point won't matter here, so leave it alone). You should now have a pink rectangle (or part of a pink rectangle) on the canvas. Without clicking anything else, enter the same size into the "Draw Rectangle" parameters for width and height on the left side of the screen and click "apply". This will give you a rectangle that's the same size as your workspace, but it probably won't be centered.

3) To center the rectangle, close the "Draw Rectangle" box on the left and (with the new rectangle still selected), go to the "align objects" area on the left and click the "Center" icon. That will now center your rectangle on the canvas - though it may be hard to see because it will match the border of your canvas, exactly.

4) Now here's the great part; with that rectangle still selected, click the "Offset" button (it should be at the bottom on the left menu under "Offset and Layout"). Select the "Inwards / Left" option, and then enter the size of border you want for the distance. So if you want a border 1" wide, simply enter 1 and click "offset". This should make another perfectly centered box in the center of your workspace which will serve as your cut vector and you won't have to mess with subtracting values and whatnot to achieve the size of border you are looking for.

5) Finally, if you don't want it to have squared edges, you can close the "offset vectors" options on the left and then select the "fillet" tool under the "Edit Objects" section. Select the radius you want and then click all 4 corners of the inner box.

-and that's it! Then you can generate your cut path like you normally would, using that inner rectangle and the 'X' method I mentioned in the previous post. As long as your stock is squared up on your machine and not angled, the border cutout should be perfectly centered and the border should be exactly the width you're looking for.

My apologies if I was a bit verbose, but I'm not sure how much experience you have with the program.

I hope that helps!

[microreefsaquariums]

I went to make the box with all the figures you gave me, but when I got to the offset section, I was only able to enter 1 inch as the border and it drew in a box. I tried entering 3.25 and it said the vectors were off, is that because I have a small work piece 6 x 4? I normally would be cutting out a large eurobrace at least 12 x 12 inches or bigger. I got close and it seemed a lot better than gambling numbers via subtraction to get the desired cut that was still not perfect. I would like to have 3.25 inch border off of 36.25 X, 21.375 Y. work piece. Can you guide me on those values? I used your 6 x 4 and was able to get as far as 1 inch border only.

Thanks,

Mike G

[dadealeus]

Sept 5, 2022 20:37:10 GMT -5 microreefsaquariums said:

I went to make the box with all the figures you gave me, but when I got to the offset section, I was only able to enter 1 inch as the border and it drew in a box. I tried entering 3.25 and it said the vectors were off, is that because I have a small work piece 6 x 4? I normally would be cutting out a large eurobrace at least 12 x 12 inches or bigger. I got close and it seemed a lot better than gambling numbers via subtraction to get the desired cut that was still not perfect. I would like to have 3.25 inch border off of 36.25 X, 21.375 Y. work piece. Can you guide me on those values? I used your 6 x 4 and was able to get as far as 1 inch border only.

Thanks,

Mike G

That's correct; because 3.25" is wider than half of either the width or height of the workpiece. In the example I provided, technically the largest offset you'd be able to make would be 2" - but you wouldn't see the resulting box because it wouldn't actually exist (2" being exactly half the smallest dimension of your workpiece - which is 4" in my example - meaning if you had a 2" wide border on both edges of a 4" wide piece of wood, the part that was left in the center would be 0" in size). Using my example, if you set the offset to 1.99", you would be able to see a tiny rectangle in the center of your workpiece.

So, for an offset of 3.25", your workpiece's smallest side would need to be at least greater than twice that number (greater than 6.5") in order to see it.

If you re-do my example, but use the dimensions of 36.25" wide by 21.375" height (instead of the 6" x 4"), you would certainly be able to make an offset of 3.25" to create a border of exactly 3.25" in size.