Linear moves at the start-toolpath / saving 100% tool costs

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Roelli
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Linear moves at the start-toolpath / saving 100% tool costs

Post by Roelli »

Hello!

I would like to solve a problem that I've got since all the time... I don't have ANY dull tool because 100% of my tools break at one point, when the end-vectors of a toolpath is reached.
I think I could save a lot of tool-costs when solving this problem.

Iam using the function of vcarve to make linear moves (50°) at the beginning of the toolpath.
This seems to work FANTASTIC!... now the tools don't break anymore.
With 50.000 turn/min and a high feed rate the tool only breaks at the end of the toolpath when the waste material falls out of the workpiece. (same problem when using a vice or a vacuum table)

Here you can see the problem:
http://www.youtube.com/watch?v=byAY83JHvaE

Somehow this feature doesn't work properly when cutting rectangular cutouts and I don't know how to fix it.
As you can see in the picture there are two cutouts with the exact same dimensions but only the cutout at the top has the 50° start moves... the other one does not have these 50° start moves. Why?

Here is the file:
https://dl.dropboxusercontent.com/u/296 ... %204he.crv

And thats how it looks like:
Image

(a feature where the feed-rate is reduced by a user defined length before the end-point of the calculated toolpath is reached could solve the problem, too - but there is no feature availabe in vcarve at the moment)
As you can see in this video the waste material doesn't even flip off the machine table when slowing down the feedrate at the end of the toolpath. (i reduced the feedrate manually)
http://www.youtube.com/watch?v=Us0DOCrhGa0

Thanks!
Roelli.
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Adrian
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Adrian »

Your start nodes are in different positions between the two rectangles.

You should be getting a message telling you that the leads have been removed because of the possibility of gouging.

Not sure if it would work for you situation but have you tried spiral ramping? I use it all the time on material that might move.

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mezalick
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by mezalick »

Adrian,
You are correct. Changing the start points will create the tool path wanted.
Michael
Attachments
bottom rectangle.JPG
top rectangle.JPG
change start point.JPG
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Roelli
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Roelli »

Adrian wrote:Your start nodes are in different positions between the two rectangles.
Yes. Seems like this is the problem. But I don't want to change the startpoint myselfs... lasts too long on big customer-files.
I don't care where the start point is... the important thing is THAT the selected function works. (should work) :D
Adrian wrote:Not sure if it would work for you situation but have you tried spiral ramping? I use it all the time on material that might move.
I tried that before... but it didn't worked as good as I thought it would. Maybe I have to check spiral ramping again.

Thanks,
Roelli.
Last edited by Roelli on Fri Feb 21, 2014 10:59 am, edited 1 time in total.
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Roelli
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Roelli »

Ok, I got it.
Press "N" to enter Node edit mode
Put mouse over the vector-point and press "P"

Image

By the way... is there any feature in vcarve which makes it possible to select "ALL OBJECTS WITH THE SAME PROPERTIES"?
Like... if there are 200x 3mm holes between 300x 4mm holes I would like to select the first object, then right click and "select same objects" or so?
Thats how it is done with a 20year old DOS CAD/CAM Software and I really love this feature.

Thanks,
Roelli.
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Adrian
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Adrian »

Edit menu, Vector Selector. That will let you select circles of certain diameters etc. The same selector is available on the toolpath itself as well and can be automatically set.

You may want to get more into layers and toolpath templates. That makes the selection of vectors incredibly easy.

Roelli
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Roelli »

Adrian wrote:Not sure if it would work for you situation but have you tried spiral ramping? I use it all the time on material that might move.
I just tried using spiral raming and the tool breaks at the 6th hole. (I had to set the feedrate XY and feedrate Z to the same value, otherwise the spiral ramping was miscalculated/too slow)

Any ideas of what can help?

Image

Image

Thanks,
Roelli.
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Roelli »

Adrian wrote:Edit menu, Vector Selector. That will let you select circles of certain diameters etc. The same selector is available on the toolpath itself as well and can be automatically set.
You may want to get more into layers and toolpath templates. That makes the selection of vectors incredibly easy.
Ah... nice! But I can only select circles, right? But what if I want to select objects with a special shape? Thats possible with toolpath templates? (I didn't understand how to use templates and it showed me chinese letters when trying this... but if toolpath templates is a solution I think I need to look into it)

Thanks,
Roelli.
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mezalick
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by mezalick »

Just a guess / suggestion....
How about trying a different type of bit,,or from a different manufacturer ?

Michael
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Roelli
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Roelli »

mezalick wrote:Just a guess / suggestion....
How about trying a different type of bit,,or from a different manufacturer ?

Michael
Yes. Same problem.
I don't think it is a problem with the tool... it's definately a problem with the toolpath calculation. So Iam trying to find a solution for this.
When I slow down the feedrate only at the end of the toolpath it works with NO problems. Slowing down the spindle speed might work, too but it lasts 1second/10.000 turns to slow down,
and no software will calculate this automatically.

Thats what I did:
Cut 2.8mm deep, then a second cut for the last 0.3mm. That works. Disadvantage: Calculating the toolpath last much longer, machine time is much longer because the machine first cuts all holes down to 2.8mm, and after all holes are cut the machine starts from the beginning and cuts the last 0.3mm.
Same for rough and finishing cuts... the machine will not do this at once.
It would be nice to have a "one-click solution" here. A checkbox with "finishing cut yes/no" and a pre-defined parameter.
For example: I make 3 cuts (the contour is 0,1mm smaller), each 1mm for rough cutting, then a finishing cut 3mm.

Trying different tools:
Same problem.

Using pocket toolpaths:
Works, but last muuuuch longer

Seems like what Iam using right now works the best... but only on round objects. At rectangular objects the start points are differently and so the first move is deleted. So I need to select all objects and correct them manually which costs a lot of time when working with large files and lots of cuts.

Thanks,
Roelli.
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by spyderxxx »

Would Paul's gadget work to edit the start points?

http://forum.vectric.com/viewtopic.php?f=2&t=19117

Ed

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Adrian
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Adrian »

Ed, not in this case.

Roelli, how are you holding the material that is being removed down? I don't cut metal but I do a lot of instrument panels in phenolic. I use double sided tape to ensure that the waste material doesn't move about when the cut is finished.

Presumably you don't want to use tabs because of the cleanup time?

Roelli
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by Roelli »

Adrian wrote: Roelli, how are you holding the material that is being removed down? I don't cut metal but I do a lot of instrument panels in phenolic. I use double sided tape to ensure that the waste material doesn't move about when the cut is finished. Presumably you don't want to use tabs because of the cleanup time?
I use a pneumatic clamping system. Same as a bench-vice but with this one uses air-pressure.
That means there is NOTHING below the material. The cutted part will just fall down. This works even better then using a vacuumtable.
The problem with the vacuumtable is: The part will flip out of the hole and when it falls down to a position where the next toolpath will be cutted.. then the tool breaks. (slowing down the feedrate say.. 5mm before the last cut is done would 100% solve this problem, but this feature is not available)

While thats the only situation which breaks the tools i only need to buy new tools because of this problem. I simply don't have any dull end mills because they just break before becoming un-usable.
This problem costs ~1000€ each year and iam trying to fix this. Not just because of the 1000€, but the cutted part can become un-usable or it need more time to start the machine again, find out where the tool breaks and start the program at this position, or before.

Here is a picture of the clamping system:
Image

Thanks,
Roelli.
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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by dond52 »

Have you tried feeding your roughing pass the opposite direction? I believe the problem is the way the waste material moves as it is nearing the end of the cut. That and the desire of the cutter to pull into the tiny point of material that is left when the waist tries to fall out. If the feed direction is reversed the the cutter will attemp to push the waste material away from itself instead of into it.

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Re: Linear moves at the start-toolpath / saving 100% tool co

Post by glenninvb »

Would a couple onion skin thick tabs solve your problem? you could pop the waste out with finger pressure. A de-burring tool would clean edge.


What is alloy of material? 5052 or similar?

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