Custom datum

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siric
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Custom datum

Post by siric »

Hi,

I have some boards to engrave but there is no corner to use for the datum and the exact centre will be problematic. Is it possible to define a custom datum like in the centre of the hole?

Thanks

Steve
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Leo
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Re: Custom datum

Post by Leo »

You can draw the hole in the center of the material with the cutting board around the hole just like you have it in your sketch.

on the machine
Pickup the hole as "X"-"Y" zero - then do the work you want to do.

If you want I can do a v-carve file for you.
cutting board.jpg
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC

siric
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Re: Custom datum

Post by siric »

Leo,

Ok, the board is already cut out. I just want to place them on the machine to do the engraving.

Steve

glenninvb
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Re: Custom datum

Post by glenninvb »

yes, change the file work origin to center if not already, offset the profile vector outward slightly and use to machine a pocket in a scrap spoil board for the cutting board to fit, save the new origin for subsequent work .... for simple engraving an etched profile line would probably work fine too but a pocket would hold work nicely

glenninvb
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Re: Custom datum

Post by glenninvb »

I should add, the method will work with most any shape as long as filets are added to the pocket to allow for sharp points, (tool clearance) and I'll usually add a finger relief for removing part

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dwilli9013
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Re: Custom datum

Post by dwilli9013 »

Lay a framing square on your spoilboard butt the handle up to the y and the cutting portion up to x. Note the position of the center of your handle hole.
Set your program x y 0 to the crotch of your framing square. If you clamp your square down you can do as many as you want of the same cutting board or any other irregular shapes you have to cut from a known origin. :)
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glenninvb
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Re: Custom datum

Post by glenninvb »

The framing square will certainly work as long as you have a reference point for an odd shape with no square sides (such as handle hole), If not the pocket or profile etched line works nicely, as well makes for a good part hold down, if snug or a couple tabs of double sided tape
It is very easy to copy the file and change the datum point to center for subsequent work, the machine doesn't care about the original datum point.. like I said a simple etched profile line would locate this job adequately with a couple clamps
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Capture.JPGnew dat.JPG

glenninvb
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Re: Custom datum

Post by glenninvb »

And to answer your original question :oops: as Leo said, you can use the handle hole as the center datum point as well... a dowel pin could locate if you have many parts, along with an etched profile line or add a reference strip to file drawing or a square ... many ways to relocate a 2d part that's already been machined on a CNC router

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adze_cnc
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Re: Custom datum

Post by adze_cnc »

siric wrote:I have some boards to engrave but there is no corner to use for the datum and the exact centre will be problematic. Is it possible to define a custom datum like in the centre of the hole?
Since no one actually answered you original question, I'll have a go.

Yes you can set an arbitrary origin point. In the the "Job Setup" there is a checkbox called "Use Offset". Positive numbers will move the "material" away from the origin cross-hair. Negative numbers the opposite.

Steven

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Leo
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Re: Custom datum

Post by Leo »

Yes it is OK if the board is already cut out. It doesn't really matter.

The Vectric file is ONLY for the programming of the cuts you want to make.

This will get the XY zero on the hole and you will orientate the cutting board on the machine the same as the orientation in Vectric then set XY zero to the center of the hole on the actual cutting board.

In fact - if you have several cutting boards, all you need is a dowel pin to locate the hole, another stop for orientation, clamp it down, press cycle start. This is partly what I do for a living.

The material size in Vectric has no bearing at all.

The only thing that matters is the text that you want to engrave and it's relationship to the XY origin point.

When you think about it - you can set the XY origin any place you feel like setting it.

The material could 1000" x 1000" and it means nothing ---- in this case.
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC

glenninvb
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Re: Custom datum

Post by glenninvb »

adze_cnc wrote:
siric wrote:I have some boards to engrave but there is no corner to use for the datum and the exact centre will be problematic. Is it possible to define a custom datum like in the centre of the hole?
Since no one actually answered you original question, I'll have a go.

Yes you can set an arbitrary origin point. In the the "Job Setup" there is a checkbox called "Use Offset". Positive numbers will move the "material" away from the origin cross-hair. Negative numbers the opposite.

Steven
I was simply thinking of ways to relocate a part that has been machined and removed from table regardless the original origin point, even with an offset datum point the part needs to be relocated? is that not correct?

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Adrian
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Re: Custom datum

Post by Adrian »

Leo did actually answer the original question in the first reply post. I was going to add the offset option as an alternative but the OP seemed happy with the answer and the thread moved on from there.

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Leo
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Re: Custom datum

Post by Leo »

siric wrote:Leo,

Ok, the board is already cut out. I just want to place them on the machine to do the engraving.

Steve
Steve - yes, I get it.

What I am proposing for you is a very simple approach.
I like KISS
Keep it simple.

Just clamp it down - set XY zero to the hole - then engrave.

Don't read too much into it.

Read my post just above this one
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC

glenninvb
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Re: Custom datum

Post by glenninvb »

Adrian wrote:Leo did actually answer the original question in the first reply post. I was going to add the offset option as an alternative but the OP seemed happy with the answer and the thread moved on from there.
sorry Adrain, didn't get that the OP seemed happy, thought that his comment was another question for aligning the part that had been removed....

jib2
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Re: Custom datum

Post by jib2 »

While your question has been certainly answered I do some similar work and her is how I do it. This method allows me to put the word anywhere on the board that I choose simply by placing the pattern of the words and centering to that pattern and NOT the cutting board. So the pattern ends up being the approximately the same size as your words to be cut. NOTE the cutting boards must be clamped square which may require you to make a fixture to do that so it is consistent.

I hope I have explained this good enough see the attached file: Notice it has a location point (datum) at its center. I cut out the words and the square outline and mark the center point from .25 MDF then table saw around the square to get the pattern.

Again this is how I do it and I'm sure their are many ways to accomplish your task.

JIB2
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demo.crv
Hope this helps
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