Welcome to MCAD Central

Join our MCAD Central community forums, the largest resource for MCAD (Mechanical Computer-Aided Design) professionals, including files, forums, jobs, articles, calendar, and more.

Register Log in

How to not cut the same material twice?

kumaichi

New member
Ok, I think I now have how to cutout my peice from a 6x6 peice of stock. I figure I'll cutout the 50mm hole, create a peice so that I can clamp it down from the id of the whole, then cut the rest of my peice of out the stock.



When I do my volume mill (after I've already cut out the 50mm whole) and run the toolpath, it cuts the 50mm whole out again. This isn't good in my situation because it would end up cutting out my hold down piece.



Can I tell Pro/E not to cut the whole out again or do I have to go into the g-code and just delete the code that cuts out the whole.



The piece I'm working with is below.



Thanks for any guidance for a newbie,



Craig



View attachment 96
 

ctarmijo

New member
kumaichi,

With a volume milling sequence, the intention is to remove a pocket of material such as your 50mm hole. Upon initial look, the part that you have needs other approaches. For example you may want to suppress the hole feature when you process the volume milling sequence and get the results you wish to accomplish. Or, you may model and assemble your fixture to the part that will fill the hole, assemble it as the fixture in your operation setup and see if Pro/E performs a gouge avoidance on the fixture (it should do it but I am not quite positive) thereby eliminating the re-cut in the hole. Plus by the looks of the part you may have to turn it around and perform a secondary operation as well as a third operation to get to the smaller hole that is perpendicular to the 50mm hole. Because of the nature of the part, it can open new approaches to milling this entire part because of the processes you need to go through to make it (also depends on the machines you have to work with).

You will find that there are many different solutions to producing a part. It is a matter of getting the best quality, and on time delivery out of the process, that will help you make some manufacturing decisions. Good luck!



Christopher
 

kumaichi

New member
Christopher,



Thanks for the reply. Yes, you are correct when you say that it will take three seperate operations. Basically, I'm looking for the most efficient/cost effective way of holding down the peice while I cut it out of the workpeice and thought if I cut out the whole first it would give me enough hold down to cut the rest of the part out.



Sorry to ask such simple questions, this is my first CNC project and I need to do a run of 30 at a time on a Rong Fu type 3-axis machine. I got quotes to produce it for me @ $30 per peice and I just thought that I could do it cheaper myself (larger profit margine.) Right now, I'm just trying to figure out the best/fastest way to produce this part.



The other thing that makes it difficult is the fact that I have that angle on the bolt boss, that will also require another tool change to a rounded bit, the volume milling sequence just cuts it square because I'm using a straight end mill.



Thanks again for your suggestions,



Craig
 

eddie

New member
I think you want to use Matrl Remove from the Machining menu after machining the hole sequence.



However, I would suggest finishing the outsides of the part with a Trajectory sequence rather than the mill volume. I like Trajectory because it is sometimes easier to control unnecessary cuts. You can do multiple trajectorys if needed for rough and finish and you can add lead in and lead outs where you have space. Use Axis Shift parameter to control depths. You can turn Cutter Comp on in the lead in also. The trajectory can be defined with an edge, sketch or curve.
 

nguy_da

New member
you have create your volume without including the hole in it. in your case modify the volume do another sketch to remove the material in the hole. volume represents exactly what you tell the software to remove.



clamp on top of the hole might not strong enough. you might want hold it on the vise first. pop some screw and locating holes around the part. machine the step on top of the hole. machine the hole to finish size. finish the top edge.





flip part over and use a fixture plate to relocate the part using the locating holes from 1st operation. machine the step on top of the hole. stop the machine put a clamp where the finish top edge is. finish the outside. about the chamfers you can use a chamfer mill to machine them from 1st and 2nd operation. or finish them when you drill the small hole. sometimes add one more tool in your operation save you more time.



no, material remove command won't help anything in this case. you just need to create the right volume for the job.
 

kumaichi

New member
nguy_da,



That worked, I didn't realize I could remove part of the volume that I created. There is one feature that I have not yet put on the peice and it is 3 #40 holes in the flat section of the peice. I'm hoping that by bolting it down by those three wholes AND the 50mm whole, I should be able to complete the job, right?



Do you think that will be enough to keep it down while I cut the peice out?



Can anyone recommend a good book? The help doesn't really help me very much.



Thanks again for all of the suggestions,



Craig
 

cncwhiz

New member
Craig,

I do not know if you will get a good finish around the profile if you just clamp it through the hole. You may need more clamping. IF you use trajectory melling, you can select aotumatic cut and use edge. Then you can select the outside profile. I dont know if your clamping setup will give you the room to finish the top of the part.
 
G

Guest

Guest
kumaichi:


I think you can pick biuld cut--skip regions pickskip 50mm hole region
 

Sponsor

Top