HST Fitting Parameters

[Sigurd]

I'm struggling to understand what the options under Linking Parameters -> Fitting are doing (Fully Trim Pass, Minimize Trimming, Machine Entire Pass). I've read the help file and I just can't make sense of it. I've always left it to default and haven't scrapped a part yet because of it, but I'd rather not have that be the judge. Thanks in advance.

[crazy^millman]

I always machine entire pass. If you look at it will allow the cut to do a .05" lift before it finished the cut. The idea behind it and I am guessing here is to not have a sharp stop, but I never want unexpected extra material in my part. To allow anything other than Machine entire pass in my mind means just that leaving extra stock.

[Colin Gilchrist]

Exactly. The idea is to fit a "radius" into the cut motion, without having to manually "trim back" the surface being cut, but I prefer to always "machine entire pass" like Ron, and manipulate the geometry if I need to do something special...

[JoshC]

some info below on this

Machine entire pass

The path of the tool will match the surface, including vertical surfaces and the corners. An arc will only be inserted at the end of the pass, and then only if it can be done so safely without hitting the part.

 

Fully trim pass

In cases where it is important to prevent over-machining, select the Fully trim strategy. The pass is trimmed back so the entire arc fits into it, but no nearer than a full machine pass link would be.

 

Minimize trimming

The path of the retract will be as close to the surface as possible, maintaining a minimum distance from the surface to fit the arc.

 

Using the maximum trimming distance

Use the Max trimming distance parameter to limit the amount of trimming applied to non-horizontal passes. When a lead arc is added to a horizontal machining pass, the length of pass trimmed off will be at most the radius of the arc. However, when adding an arc to a steep finishing pass, the total length of pass trimmed – that is, the trimming distance – can be much greater, as shown in the picture below. To avoid this, the Max trimming distance limits the trimming distance; if the amount trimmed would exceed this value, then no arc is used. Instead, the whole pass is machined, and a straight vertical motion is added.

[crazy^millman]

4 hours ago, JoshC said:

some info below on this

Machine entire pass

The path of the tool will match the surface, including vertical surfaces and the corners. An arc will only be inserted at the end of the pass, and then only if it can be done so safely without hitting the part.

 

Fully trim pass

In cases where it is important to prevent over-machining, select the Fully trim strategy. The pass is trimmed back so the entire arc fits into it, but no nearer than a full machine pass link would be.

 

Minimize trimming

The path of the retract will be as close to the surface as possible, maintaining a minimum distance from the surface to fit the arc.

 

Using the maximum trimming distance

Use the Max trimming distance parameter to limit the amount of trimming applied to non-horizontal passes. When a lead arc is added to a horizontal machining pass, the length of pass trimmed off will be at most the radius of the arc. However, when adding an arc to a steep finishing pass, the total length of pass trimmed – that is, the trimming distance – can be much greater, as shown in the picture below. To avoid this, the Max trimming distance limits the trimming distance; if the amount trimmed would exceed this value, then no arc is used. Instead, the whole pass is machined, and a straight vertical motion is added.

Care to explain what is meant by over machining in the Full Trim Pass explanation?

[JoshC]

14 hours ago, crazy^millman said:

Care to explain what is meant by over machining in the Full Trim Pass explanation?

i pulled that from a help section of an older version since it had more info and pics, but as far as what is meant by over machining im not sure what whoever wrote this up originally meant by that. Its pretty easy to see the differences between all 3 of them in the file attached though, i setup 3 toolpaths and intentionally made the path retract after each pass, then added an avoidance, and you can see how the retracts are slightly different around the avoidance surface from each toolpath example.

Fitting-test.mcam

[crazy^millman]

19 minutes ago, JoshC said:

i pulled that from a help section of an older version since it had more info and pics, but as far as what is meant by over machining im not sure what whoever wrote this up originally meant by that. Its pretty easy to see the differences between all 3 of them in the file attached though, i setup 3 toolpaths and intentionally made the path retract after each pass, then added an avoidance, and you can see how the retracts are slightly different around the avoidance surface from each toolpath example.

Fitting-test.mcam 3.35 MB · 0 downloads

Fair enough I would think the help would be a little more cautious about something like that.  Good example I was looking in the new documentation also and it was lacking to help me understand it.

[JoshC]

Just now, crazy^millman said:

Fair enough I would think the help would be a little more cautious about something like that.  Good example I was looking in the new documentation also and it was lacking to help me understand it.

Yea the help is a bit lacking on this specific topic, back in the X days the help had an entire video about this topic that i thought was really useful, i cant seem to get the video to work on my modern system unfortunately because it will either tell me that internet explorer doesn't support adobe flash anymore or that it cant find an app to play the vid in app store, but that video there i wish i could share or even review myself still because it used to be pretty helpful. If anyone knows if a way to convert that vid to like .mp4 or something a modern pc can actually use please let me know cuz i would love to get a copy of that vid again and think it was awesome when we used to be able to find videos in our help sections in mastercam