A strategy combining Rest Machining Contour & Pencil for cleaning out corners

[rjolly49]

I started programming initially with Cimatron, a 10+ year old version of it at that several years ago. Cimatron has an operation called "Remachine" with an option of clean up that worked great. Similar to Rest Machining, you would enter in a previous tool size, say a 1" ball, and the operation would clean out any stock that a 1" ball had left behind. You would then specify values for down and side steps separately. The operation would then clean out all vertical corners/fillets as HSM's 3D contour strategy does, but it would also clean out any corners/fillets that were more horizontal just as the pencil strategy does. The way I do it now is to use Rest Machining Contour first, selecting or drawing up all boundaries encompassing vertical corners, then creating a separate pencil operation for the areas with lower slope. I can't allow the pencil strategy alone to clean out all excess stock in corners, especially in cases of having undrafted walls because the shaft will clash. This approach produces great results but is more time consuming than I'd like.

I've also tried using Pocket to do this because it should work as I've described above but I haven't gotten very good results. I think part of this is there isn't a Rest Machining option of From Tool like there is within contour. When I'm working on a part with 2000 surfaces and 20 operations, generating the Pocket operation which looks at all previous operations takes an incredible amount of time. If the toolpath isn't ideal or comes with too much noise, even with the Ignore Cusps value adjusted, I end up spending far too time on just one operation. There are times I need to clean out corners stepping down in tool size 5 times so this can be a very lengthy process which is why I do the 3d contour/pencil approach. I also seem to get much more choppy, gaps in between segments of toolpath than pencil gives me.

Photo is attached of Cimatron's Remachine operation (1.jpg) and a quickly made example of HSM Pocket results. 

[rjolly49]

Here is another example of using Pocket which doesn't give me nice flowing toolpath like pencil does on areas with low slope angles

[al.whatmough]

This appears to be a request for "hybrid" finishing strategies. 

In the same way, we should have parallel + Contour.... 

Is that correct?

[rjolly49]

@al.whatmough I could definitely see hybrid finishing strategies of all sorts being beneficial but my idea is more specific to our application. In our case, and I would think in general a lot of parts people program have both vertical and horizontal corners/small fillets that need to be cleaned out after the tool they select for finishing does it's work. I like HSMworks but the main issue I've always had with it is how I have to go about picking out corners/small fillets and how it's at least a two step process yielding less than ideal results at times.

To answer your question though I'd say not exactly, in that I'm not looking for a selection of hybrid strategies, just a hybrid strategy for cleaning out corners. If you haven't looked at the attached file 1.jpg in my initial post, take a look because that's exactly what I'd like to see implemented.

[Laurens-3DTechDraw]

@rjolly49

I looked at your 1.jpg but man that is a weird toolpath. On the bottom filled it morphs into one point and then does the side edge in Z-stepdowns.

You know btw about derived operations? If you have made the 3D Contour you should be able to make the pencil with a few clicks.

[rjolly49]

@Laurens-3DTechDraw I think the toolpath looks odd because I selected an option of "along contour" within that operation which creates a smooth flowing entrance to each pass and many times does come from a single point. I can select other options and it won't do that and the pencil equivalent within that operation looks just like HSMworks' pencil.

I use derived operations from time to time but typically not for pencil because I have my expressions and defaults set in a way that I only need to make a click or two anyway. The time consuming part is selecting or drawing all of the boundaries I need creating the rest machining contour operation. If I don't create or select boundaries and just do a blanket rest machine, HSM will put toolpath on all fillets, even horizontal ones. That's a waste of time because the upcoming pencil operation will machine the same areas. I'd also prefer to allow the pencil operation to machine those areas instead of selecting the time consuming rest machining by previous operations options, because pencil leaves a very nice finish by taking side steps inwards towards side walls on more horizontal of fillets. Another issue is after I select all boundaries and have my contour operation as I'd like, many times the pencil operation will have it's toolpath climbing up the vertical fillets that have already been machined. Again, I like to avoid using rest machining by previous operations because on files like this and much larger ones, it's very time consuming. Besides that, I'm also not a fan of having to regenerate those time consuming operations if I happen to make a tweak to any prior operations. 

Here are two examples of similar files. You can see in the HSM file all of the boundaries I created. I have opted to just select the vertical fillets themselves as boundaries instead of drawing them as sketch at times as well. I can't always do that because sometimes there will be sharp or very small fillets in the vertical corners in some areas, and larger fillets that still need attention in others meaning the boundary option or offset would need to be different in each case. The other screenshot is from Cimatron which I simply selected the previous tool so it knows what areas to clean up, and then a down and side step. I didn't need to select or create any boundaries and it created the perfect toolpath catching everything necessary. Another bonus of Cimatron's method is I don't need to play around with overthickness values trying to find that perfect number. I know which values generally work great for every tool but for example when there's a slot that I need a tool to go in but my default overthickness value creates the hypothetical tool that's too large to fit in there it doesn't work out nicely. In that case I need to create two pencil operations, one with my typical setting that picks up all fillet sizes that the previous tool missed, and one that is smaller yet large enough to see that slot as needing attention.

Using HSM, I have tried playing with slope values hoping that would be the answer but that doesn't work as hoped for contour nor pencil. Another thing is, when there are a lot of large enough fillets I do select a finishing tool that will leave the fillet in the part without needing to clean out after the fact but depending on the part this isn't always feasible. On this particular part I thought I could use pocket with rest machining but that leaves me using the "from previous operations" option because there isn't a "from tool" option within pocket. I adjusted my tolerance from my usual .0004" to .01" (which I'd never use such a high number) and waited several minutes and it was maybe 5% done and was also putting toolpath in unnecessary areas leaving me to manually trim it all afterwards. I adjusted the ignore cusps setting several times and wasn't able to get what I wanted.  In general, the parts I toolpath aren't as friendly as this one where most surfaces are flat that I can get away with using pocket either. 

[al.whatmough]

Batch processing ideas that are 10+ months old with less than 5 votes. This is in no way to suggest the idea isn't a good one. However, the lack of votes tends to mean that the community feels other ideas should be given a higher priority. Feel free to tag me if you feel an idea wasn't given enough of a chance. We are more than happy to have a conversation on any of these ideas.