[CadRhino]

Thanks for posting this, Ray.
I have been doing this very same procedure but have only done one at a time then manually re-established my Z zero which is a pain.
Anyone who uses Sprutcam - do you know if you can do this same function (G52) to get multiple parts milled/slitting saw?
I assume you can just have never figured out how to do it.
Thanks

I'll give you one other option you may want to consider. It's not the fastest method, but is very easy, and works extremely well:

Use round bar stock, mounted vertically in a 3-jaw chuck mounted to the table. This allows you to machine 5 sides, then use a slitting saw to part it off. After doing one, use G52 to shift the Z origin down, and you can cut another one. I use this method often for cutting small parts that would otherwise be difficult to hold, and/or require turning the parts over part-way through machining. I can typically get about a half dozen parts from a single piece of stock, the limiting factor typically being the rigidity of the setup when the stock is at its longest. That can often be overcome by just using conservative cutting parameters.

Here's a part I used this method with just a few days ago:

http://www.cnczone.com/forums/attach...0&d=1441401980

Regards,
Ray L.

[MetalShavings]

Thanks for posting this, Ray.
I have been doing this very same procedure but have only done one at a time then manually re-established my Z zero which is a pain.
Anyone who uses Sprutcam - do you know if you can do this same function (G52) to get multiple parts milled/slitting saw?
I assume you can just have never figured out how to do it.
Thanks

I considered using this method for other parts I've made. In the end, the thing that kept me from doing so was that with my metal stock held in a vertical position, I would only have been able to machine one or two parts at a time.

With the geometry of these small parts I've been making, I can't see this method working as well as holding my metal stock horizontally and milling them that way instead but, I can see the benefits of doing it as you've described for parts of certain shapes though. I think that in terms of machining and software issues, I've nearly gotten my small parts dialed in.

I just need to make a couple more fraction-of-an-inch measurement adjustments and I'll be able to make batches of them with boring regularity; that's if demand for them increases. If not, well, it was a good learning experience.

MetalShavings

[kstrauss]

Did you use soft jaws to machine the back side of the piece?

[SCzEngrgGroup]

Did you use soft jaws to machine the back side of the piece?

Was that question for me? If so, the answer is no. It was machined entirely from the top. The under-cut and parting were done with a slitting saw, so after parting, indiidual, fully finished parts were left sitting loose on the table.

Regards,
Ray L.

[SCzEngrgGroup]

Thanks for posting this, Ray.
I have been doing this very same procedure but have only done one at a time then manually re-established my Z zero which is a pain.
Anyone who uses Sprutcam - do you know if you can do this same function (G52) to get multiple parts milled/slitting saw?
I assume you can just have never figured out how to do it.
Thanks

Worst case, you can hand-edit the g-code to do this. It requires only two lines of code:

First, when you start a new piece of stock, manually do:

#100 = 0

Then, before each iteration of the code, do:

#100 = [#100 - n.nnn] (n.nnn = the "step down" for the next part)
G52 Z#100

Regards,
Ray L.

[CadRhino]

Gulp, I guess I need to get my feet wet hand coding some time.
Thanks for the code.

Worst case, you can hand-edit the g-code to do this. It requires only two lines of code:

First, when you start a new piece of stock, manually do:

#100 = 0

Then, before each iteration of the code, do:

#100 = [#100 - n.nnn] (n.nnn = the "step down" for the next part)
G52 Z#100

Regards,
Ray L.

[kstrauss]

Was that question for me? If so, the answer is no. It was machined entirely from the top. The under-cut and parting were done with a slitting saw, so after parting, indiidual, fully finished parts were left sitting loose on the table.

Regards,
Ray L.

Yes, it was for you! I just assumed that there were pockets, chamfers or other features on the bottom of the piece which would require milling from the bottom. Thanks for the clarification.

[mountaindew]

do you know if you can do this same function (G52)

FYI G52 Is not a valid g-code if you are using path pilot

[CadRhino]

Thanks Mountain Dew
I know you are really proficient in sprutcam.
How would you go about programming it.
Thanks

FYI G52 Is not a valid g-code if you are using path pilot

[kstrauss]

See MEW Issue 213 : March 2014 for some info on using G92 as an alternative to G52.

[SCzEngrgGroup]

FYI G52 Is not a valid g-code if you are using path pilot

So you should be able to accomplish the same thing with G92. I believe this would do it:

G0 Z1
G92 Z[1.0 + n.nnn] (n.nnn = step-down for each part)

I've never used G92, so I'd certainly test that before actually using it. It will also require re-setting the origin when you load a new piece of stock, presumably by doing:

G0 Z1
G92 Z[1.0 + [n.nnn * p] (n.nnn = step-down for each part, p = # parts cut in last run]

Regards,
Ray L.

[CadRhino]

Thanks, I will check it out.