Get rid of long linear lead in and lead outs in 3d contour

[Anonymous]

Since HSMworks 2016 version 2.405 the way lead ins and lead outs are created has been different. Now, if a larger safe distance is specified there is a long linear lead in/out attached to the specified radius. The sweep angle also doesn't seem to do anything when it's value is changed. There is a photo attached. The long linear lead in/out is an issue when you rough out a pocket defined by a smaller boundary. If you go back in there to finish using a 3d contour strategy the long lead in may plunge into stock that hasn't been removed yet. 

[Laurens-3DTechDraw]

 Do you compare two specific versions or do you know in which version this changed?

I'm pretty sure this is wanted behaviour, but that can be debated on the forum of course.

If the safe distance is 5mm the best way for the toolpath to listen to that is to move tangent to the end of the lead-out until it's 5mm clear of the model and then retract and vice versa for the lead-in. I mean otherwise the safe distance would be useless.

[Anonymous]

Yes HSMworks 2016 2.405 was the last version that didn't have the extension on lead ins and outs. The safe distance from that version and all prior versions seemed to only pertain to the height when the tool would go from rapid to feed moves. Now if I set my safe distance very low so I don't get the long lead ins, the tool will rapid into the stock when I take large stepdowns like .200". If I set the safe distance at .220" so the tool doesn't plunge into my stock, it will then lead in from potentially outside of the boundary I used for my pocket strategy. I could open up my pocket boundary by the extra .200" or so but due to fixturing and clamps, this isn't always ideal either. Maybe a good solution would be just how its done with stock to leave that there could be a safe distance setting for walls, and safe distance setting for floors.

[cj.abraham]

This is already logged as ticket CAM-6080 and is being looked at.

[Laurens-3DTechDraw]

 @cj.abraham can you elaborate?

I mean I'm pretty sure the system does what you tell it to do.

And I rather have it that way than change it back because of legacy reasons.

[Anonymous]

I'd be interested to see any examples anyone has of the way the lead ins used to be generated, up until last year, where clashes occurred or any issues were experienced. It seems that the way lead ins used to be computed would be fine because if a person roughed a part leaving say .03" finish stock on the part, they could just use a .031"+ lead in and all would be well. Also, when mousing over the safe distance field it says the safe distance is measured after stock to leave has been applied so I don't see how a clash would occur anyways. The issue for me happens on every one of the several dozen parts a week I program. The parts we machine are held down to 2"x2" stringers so the bottom of the majority of the part has nothing underneath it. I rough the part to about 1/8" of the bottom of the stock and then I switch to the 3d contour strategy. The reason for this is the majority of parts I program are very oddly shaped that we can't pre-cut our stock too close to the finished part shape. Because of this we can have large areas of stock extending 6"+ from the part's shape that need to be removed at some point. If I let the pocket strategy cut all the way down to the bottom of stock or beyond, these areas start to vibrate excessively and in the past have broken off prematurely sometimes breaking away large pieces of the actual part or they may cause other issues. To get around this, like I said I pocket down to about 1/8" from the bottom and then switch to 3d contour which then machines tangent to the part, cleanly cutting away any excess stock. It only takes one pass with 3d contour because I set the stepdown to .200". With the new way lead ins are generated, I have to set the safe distance to more than .200" otherwise the cutter plunges into the remaining stock at a rapid feed rate. If I set the safe distance to more than .200" to avoid this, depending on part geometry we may run out of machine travel, push our luck with hitting clamps, or if I only machined certain areas contained by boundaries the tool may plunge into the full height of stock where I haven't yet roughed anything away. I'm aware that because a lot of work we do uses wood or other relatively soft materials our methods are likely pretty unique and others may not experience the same issues with this. I just don't quite understand how the previous way lead ins were done for years would have any adverse effects because the lead in radius or length can be used to create a safe distance in X and Y and the safe distance value provides the safe distance for Z. Unfortunately for me, if I need the safe distance to prevent clashes on Z moves, I then get an excessive safe distance in X and Y with no way to change that.

[Laurens-3DTechDraw]

@Anonymous My problem is exactly that I don't think the lead in's are for making sure you plunge outside of current stock.

The safe distance is applied after the stock to leave of that operation. Not the previous operation. I can't always know/calculate exactly how much stock is everywhere and thus how big of a lead-in I need. Also this could cause the operation to not generate in cavities where the lead-in radius would be too big to enter the cavity. So if I give in 5 mm of safe distance I know it won't run into stock that is still there but still be able to machine everything.

Also how it now works is how all the parameters should work in the system. I mean I could agree to two safe distances. But no to make the toolpath not listen to the current safe distance properly.

[Anonymous]

I understand and agree with the first portion of how the safe distance is calculated. The change to the safe distance application only applies to the wall safe distance, as floor safe distance is computed exactly the same regardless of version it appears. As far as having to know how much stock is everywhere, that would be the wall stock to leave value that was entered into your roughing operation. Seeing how the changes to the lead in generation only apply the wall safe distance and not floor, a person would just have to enter a lead in value slightly larger than their wall stock to leave value within their roughing operation. In the versions prior to the change, you could leave your safe distance at 1/4" if you wanted which basically just tells it to start the feed move 1/4" above the cutting height, so you could do that to avoid vertical move clashes and your lead in value would take care of XY clashes. Before creating this thread I did consider small cavities so I looked back at some files that I've programmed like that and there aren't any worries there. If you enter a lead in too large for a cavity, the toolpath still generates but truncates the lead in so it fits. I'm not sure (due to not having any recent versions) what would happen in a cavity if you have a safe distance value that wouldn't leave enough space for the cutter to even feed plunge to the depth of that pass. without violating the safe distance of one wall or another. The safe distance value in these cases seems to be the only factor to keep the tool from rapid plunging into your stock and seeing how this would be a matter of plunging into stock on the floor and not wall, HSM would handle this the same way regardless of version.

I am all for two safe distances and believe that would be the best option, giving the user the most control.

[Laurens-3DTechDraw]

The safe distance has to be bigger than the stock to leave when you are finishing a non-vertical wall. If I have roughed a face that is 45 degrees with a stock to leave of 0.5 mm but a fine step-down of 5 mm there is more left than  0.5 mm. So I would need more safe distance.

[Anonymous]

Yes there's no doubt about that. I actually have my safe distance default set to several times the stock I leave from roughing. That way when it encounters areas with a lower slope angle, it feeds into potential stock instead of a rapid move into it.

[Anonymous]

I've now been forced to update due to packaging changes. I found that with the versions since 2016 2.405, the safe distance doesn't apply to both XY and Z like I thought previously. It went from being only your safe distance in Z (2016 2.405 and earlier), essentially letting you decide how far above your feed height the machine changes from rapid to feed, to now going at rapid speed right to the toolpath height. I wish there was a setting, basically how an R value is used in a drill cycle, that a user could enter how far above the actual machining height that the tool will start to move at your designated feed speed.

[Laurens-3DTechDraw]

@Anonymous

I know this is kind of old now. But isn't the Ramp Clearance height the parameter to set how high about the toolpath level it starts with feed moves?