How to Set Up a Job with Non-rectangular Material

[DyeHard]

I'm new to VCarve Pro and I'm currently making my way thru the tutorials.
I need to set up a job that begins with a piece of wood that doesn't have a simple flat top surface but have been unable to find a reference that provides any insight on how to accomplish this.

I need to carve shapes that have some areas that may extend an inch or two above the rest of the carving. For example, I have a 1' by 2' piece of wood that is 1" thick but there are 3 2"x2" areas where I need parts of the carving to be 1" higher than the top surface ( 2" depth total). I certainly prefer not to start with 2" thick stock and waste most of the top inch. My preference is to prepare the stock by gluing the 3 2"x2" pieces of wood precisely where they need to be on the 1' x 2' stock and then carve it out. Since I have to perform this style of cutting often I'm looking for a reasonably efficient way to handle this type of job.

So how can I define a VCarve Pro job that uses non-rectangular wood?

If this isn't supported in VCarve Pro, is it supported in Aspire or another Vectric product?

Thank you for your help.

[4DThinker]

You can't.

But you can cut the highest areas, then set a start depth for the low areas that will eliminate the need to cut air before getting to the lower areas.
Set the material thickness to its maximum thickness, then cut your highest areas first, then set new start depths to begin the lower areas.

[IslaWW]

I would setup a job with the size that your irregular blank can fit in at the thickness of the main blank with the blocks added. Add a vector (for you) that represents the actual material shape. Add vectors that represent the raised blocks, maybe even using a .020" deep pocket to align them.

Machine the areas that include those blocks, if possible. For the balance of the machining on the lower sections, use a 1" start depth. Don't forget to have your Z clearance high enough to miss the raised portions.

You will have to segregate the toolpaths that do and do not have the start depth

[DyeHard]

Thank you for the information. While reading the replies I had what I believe is a similar work around and I'd like to get your feedback.

Using my example, what if I define the job in VCarve as 12" x 24" and 2" thick to include the total height of the real world job. Then I define a pocket toolpath that will cut the virtual VCarve material so it matches the real world wood on which I have glued the 3 1" x 1" blocks of wood. This would be a Virtual Job Setup Toolpath that I would not upload to the CNC. The virtual VCarve material would now look like this:

VCarve virtually prepared wood

Now I can define the toolpaths that will cut into this material since it matches the real world material on the CNC. If I don't upload the Virtual Job Setup Toolpath to the CNC, but I do upload the rest of the job toolpaths, I should be able to intelligently cut the job without cutting empty air. The CNC should also know where the raised blocks are so I don't have to exaggerate the Safe Z height for the job. I think this has the advantage of keeping the VCarve design simple so it can accurately visualize the toolpaths within a single block of wood.

I would need to:
+ Make sure the virtual and real world materials match. I could define the raised blocks as slightly larger than they actually are in case there was a slight misalignment.
+ Set up the job on the CNC using the height of the 3 raised blocks, 2", as the material height.

So I guess the question is, should this approach work?
Will I encounter any problem if I don't upload the first toolpath I used as the Virtual Job Setup Toolpath?

Thanks for brainstorming this approach with me.

[LittleGreyMan]

DyeHard,

This is the right process to visualize the final result.

As long as your workflow is logical and you "make sure the virtual and real world materials match" (which is the key in every job), you won't have any issue.

I often use these virtual toolpath, for example when I project a Vcarve toolpath on an object which has been machined with another CAM: I run a virtual finishing tool on the model to get it virtually cut (no roughing needed in a virtual world) and see the result of the Vcarve simulation.

[DyeHard]

Thanks LittleGreyMan . It's good to know that others have thought this through and have a working solution. Will definitely be using this method often.

[ger21]

If I don't upload the Virtual Job Setup Toolpath to the CNC, but I do upload the rest of the job toolpaths, I should be able to intelligently cut the job without cutting empty air.

Your "Virtual Job Setup Toolpath" itself does not prevent you from cutting air. It just lets you see what you are starting with.

Aspire does not take previous machining into account when creating toolpaths. (except when projecting toolpaths onto a non flat surface)

[LittleGreyMan]

Thanks for correcting my post, Gerry.

I missed the air-cutting part of the question.

You can't avoid it with 3D toolpath as Vectric products don't manage custom raw material. The raw material is always a parallelepiped.

Gary posted a solution for that. Be careful and follow his advice regarding the Z clearance for the lower part.

[SteveNelson46]

Maybe this video on YouTube will help.

[DyeHard]

If I don't upload the Virtual Job Setup Toolpath to the CNC, but I do upload the rest of the job toolpaths, I should be able to intelligently cut the job without cutting empty air.

Your "Virtual Job Setup Toolpath" itself does not prevent you from cutting air. It just lets you see what you are starting with.

Aspire does not take previous machining into account when creating toolpaths. (except when projecting toolpaths onto a non flat surface)

I'm having some difficulty understanding the information on toolpaths. When a previous toolpath clears material the next toolpath doesn't expect that material to still be there, does it? How can the software make intelligent decisions if it doesn't take previous toolpaths into account when creating new toolpaths? Is it up to me to provide that intelligence as each new toolpath is created?

Is this only an issue when a previous toolpath is non 3D followed by a 3D toolpath?

As for the "cutting air" information, this seems like it would only be true if I am required to upload every toolpath I create. Am I required to upload every toolpath? If the software doesn't take previous toolpaths into account when new toolpaths are created it would lead one to think that each toolpath is independent and that I would be able to upload only those I saw fit to upload. It seems that not uploading the virtual toolpath would have the effect of not "cutting air" in that case.

Sorry for my confusion but I'm really trying to understand how to best use toolpaths to accomplish my project design goals. I really don't want to design myself into a dark corner.

[LittleGreyMan]

In any CAM software, you have to consider 2 toolpath types in 3D:
-roughing toolpath
-finishing toolpath

Roughing toolpath is intended to get rid of most of the raw material, leaving only a skin on the model. The depth of the skin is set by the machining allowance.

Finishing toolpath is intended to remove this skin and always follow the model surface. You are supposed to run a roughing toolpath first*, but the software doesn't check this.

All toolpath are independent and you have to manage them. The toopath simulation will help you checking your process.

Aspire provides a manual technique for rest machining: removing only material left by a bigger tool in the areas this tool couldn't reach. AFAIK, Vcarve lacks the modelling features to perform this.

There are CAM packages that manage previous toolpath (or referenced toolpath) to calculate a new toolpath. But there are generally much, much pricey than Vectric products.

* except in some cases (soft material, sturdy finishing bit with a sufficient depth of cut, low Z variations, …) that you will learn by experience

[martin54]

If I don't upload the Virtual Job Setup Toolpath to the CNC, but I do upload the rest of the job toolpaths, I should be able to intelligently cut the job without cutting empty air.

Your "Virtual Job Setup Toolpath" itself does not prevent you from cutting air. It just lets you see what you are starting with.

Aspire does not take previous machining into account when creating toolpaths. (except when projecting toolpaths onto a non flat surface)

I'm having some difficulty understanding the information on toolpaths. When a previous toolpath clears material the next toolpath doesn't expect that material to still be there, does it? How can the software make intelligent decisions if it doesn't take previous toolpaths into account when creating new toolpaths? Is it up to me to provide that intelligence as each new toolpath is created?

Is this only an issue when a previous toolpath is non 3D followed by a 3D toolpath?

As for the "cutting air" information, this seems like it would only be true if I am required to upload every toolpath I create. Am I required to upload every toolpath? If the software doesn't take previous toolpaths into account when new toolpaths are created it would lead one to think that each toolpath is independent and that I would be able to upload only those I saw fit to upload. It seems that not uploading the virtual toolpath would have the effect of not "cutting air" in that case.

Sorry for my confusion but I'm really trying to understand how to best use toolpaths to accomplish my project design goals. I really don't want to design myself into a dark corner.

Every Toolpath is completely independent & assumes your block of material is the stated size in the job set up, the virtual job you want to use is ONLY a way for you to visualise what the finished part will be like & to help you generate the toolpaths you require to complete that job.

Oh just a quick note, 3D is slightly different as you can project a toolpath on to a 3D surface which is how LGM adds his Text to his 3D models

[ger21]

How can the software make intelligent decisions if it doesn't take previous toolpaths into account when creating new toolpaths? Is it up to me to provide that intelligence as each new toolpath is created?

The software does NOT make these intelligent decisions. Yes, it's up to you to make them.

[DyeHard]

Thanks for all the coaching guys. It's obvious that I need to get some experience under my belt.

This has helped to give me perspective that I'll use as I continue learning the software.

Thanks again.