Opti Rest: Wasted moves.

[MotorCityMinion]

How do you stop Opti rest from needlessly re cutting areas that have already been machined? I'm going through a Mill level 3 tutorial and the rest mill tool keeps cutting the same walls as the previous tool did. I know I could create boundaries and make multiple ops but it defeats the purpose. I've also tried increasing the stock to leave with a looser cut tolerance for the rest mill tool path and have mixed results with that.

 

Added. I'm also getting quite a few cuts that are conventional. What's up with that?

[Brewster]

Have you tried selecting stock model as a previous OP? It seems to work well for me.

[MotorCityMinion]

Yes stock model is in use as it's actually part of the tutorial. Perhaps whats taking place happens because the step down / step up and radial DOC are different between the 2 tools / ops. The rest path sees the remaining stock on the walls and decides it needs to clean up / refine these areas. IMO It should be staying out of these areas that the previous tool path could reach as the stock to leave and tolerance are the same.

[cadman2112]

Try telling the Rest cut to leave .001 more stock.

 

I Know, shouldn't have to but I have found in many cases this will get it

[MotorCityMinion]

"Try telling the Rest cut to leave .001 more stock."

 

" I've also tried increasing the stock to leave with a looser cut tolerance for the rest mill tool path and have mixed results with that."

 

Up to .002. already. Still gives me grief.

[Chris Rizzo]

Try ignore small cusps, and experiment with adjust distance. Try around .020 for starters.

[Redfire427]

I have found that when using this tool path, I get the best results when I use " roughing tool " as my source for calculating the rest passes. This way is doesn't calculate cuts on the small cusps left in previous toolpaths. It is a bit of a "it and miss" process to find something that works efficiently. I have also used the suggestions listed above by others with limited success too.

 

Carmen

[GnoGueyJose]

Hate to say it but this is one of those toolpaths that is hit and miss. I use it all the time, but the percentage of times that I guess right the first time is about 75% now. At first, it was about 25%. It just takes time to get a feel for it.

[Roger Peterson]

any of the methods other than using a tool will look for cusps or steps left in the material. Using tool will basically only look at internal corners. The ignore small cusps is what you need to use. it doesn't take much of a cusp to be .020" thick. I usually set my ignore value to slightly less than programmed stepover and get reasonably good results. But again it's supposed to be looking at where material is left behind based on where the previous tool cut or a stock model so you will get cuts in those areas.

 

 

HTH

[The_kid]

I've recently had a glimpse of where I am on the amuture vs prefessional gap. I was told that it takes little skill to take out 95% of the material it's the 5% that is where all the skill is required. I like to play around with mold cavities at home but my laptop chokes hard in verifiy so it makes it nearly impossible to practise this. I'd like to hear how most of you are doing this sort of work.

[Newbeeee™]

^^^ this is exactly right. Haven't used opti-rest yet (as still on X5 but X7 is soon woohoo) but use optirough for just about everything.

And within a couple of minutes you can have 95% of material gone - it's bloody brilliant (Englishman getting excited here )

It is the last 5% that takes the time, and to be honest we usually use edge curves and then the 2D paths to finish because we have comp to control sizes, and then can drive a spot drill around everywhere to debur the thing. Where we have 10 cnc's and only 3 (sometimes 4) operating, we like to get the parts off consistent and finished (because deburring can be problematical with sausages for fingers )

 

BTW - I'd love to spend some time with Rickster (or one of you mold - or is it mould guys) to see how you do what you do.

I'm sure it would speed up alot of what we do.

[The_kid]

I understand the fundementals of how these things get done. I just need the seat time to do it. the computer at work is the only thing I have that will process these kinds of tool paths. yeah opticore is pretty sweet the step up is great and makes a lot more sense then alternitives.

[MotorCityMinion]

Hey. You two up above. Stay on topic or get a room, this is my thread.

 

For those interested in following along: X6 Mill Level 3 book. Tutorial #4, Op 3 Opti rest with a 3/16 ball.

 

Compute remaining stock from: One other operation. Use remaining stock as computed.

Tool path size = 1738.1K, time = 51m:47.05s. WTF.

 

Compute remaining stock from: One other operation. Adjust remaining stock to ignore small cusps =.02.

Tool path size = 817.9K, time = 27m:55.90s. Excellent.

 

Compute remaining stock from: One other operation. Adjust remaining stock to ignore small cusps =.05.

Tool path size = 745.5K, time = 25m:28.63 Awesome.

 

Compute remaining stock from: Roughing tool. Can not adjust for cusps.

Tool path size = 556.5K, time = 18m:3.56s. Too chunky, but it actually did a better job at roughing the handle area than all the other settings. Changing step down/ over / up settings and sacrificing some cycle time might just yield more satisfactory results. I'll spend more time messing with this.

 

Compute remaining stock from: Cad File. Epic fail, way too much goofin around for me at this time, after selecting the saved STL from the first roughing op.

 

All of the above will require a semi- finishing routine no doubt.

 

In place of Opti rest, I set up a SF contour routine with Helix, shallow and flats enabled, one way cutting. Size was 214.1k and time was 1h, 17 min. This took considerably longer that opti rest but produced much closer to near net finish, probably not requiring a semi finish path. It also took longer to set up the tool path parameters in order to avoid collisions and required more skill where as Opti rough was pretty much point, shoot, get er done. IMO, which route to take is a matter of preference and contains too many variable to determine the best outcome for all machining scenarios.

 

For all that helped, I thank you as we got some excellent results with these tweaks.

[Newbeeee™]

Hey. You two up above. Stay on topic or get a room, this is my thread.

ROR.

This is the interweb - you should know that topics *start* in the right direction but soon move right off course!

[Newbeeee™]

BTW - MCM great info (as always).

I didn't know you could adjust for cusps....

 

To add something that *may* be useful is to underline what Carmen said. With the historic restmill paths, we usually use from roughing tool, and this gives us consistent results.

We were told to do this back in the day by Nick @4D (our reseller). See Nick, I do listen to you