Cnverting Aspire toolpaths for 4th axis machining

Cnverting Aspire toolpaths for 4th axis machining

Postby Greolt » Wed Sep 02, 2009 3:04 am

Whenever 4th axis work is mentioned on this forum there is always quite a bit of interest and the recent anouncement of a new version of the Indexer Wizard has been no exception.

Some people are keen to set up a 4th axis or already have one and want to get more use out of it.

So I wanted to start this thread to explore the possibilities of combining Aspire and a 4th or rotary axis

There are many big dollar CAM programs that will do all the bells and whistles but many like me have no intention of selling their offspring to pay for it.

We on this forum are Aspire users and all agree that it is a fantastic and capable tool. This is the Vectric forum so apart from some "Helper" utilities please lets keep the focus on Aspire or other applicable Vectric software.

The first method I will show is a 3D model from the Aspire library added to a very basic shape.

This underlying shape can very easily be done with a top and bottom rail with a two rail sweep and then a clipart model added on top.

Material size is calculated at the finished diameter times Pi (3.1416). For example I want 80mm for the largest finished diameter so I make my material 80 x 3.1416 = 251.328mm in the direction that is going to be rotating. In my case that is the X direction.

I also add a little bit for a cross over of the join. Say 2 or 3mm. So my material in this case is 254mm in the X, 120mm in the Y, and 40mm (or half the diameter) thick. This thickness is not necessary but makes things simpler later on. Especially at manual tool change time.

As you can see in the pics my model is approx 15 or 20mm thick. Place the model position at the top of material in "Material Setup" and Z zero at the bottom of material. Extra material thickness can be allowed for if stock is bigger but top of model should still be at 40mm from bottom of stock.

I created a roughing toopath with a 1/4" ballnose. Raster in the Y direction. Then a finish toolpath with a 1/8" ballnose also raster in the Y direction. The Y direction in this case means that the tool goes along the axis of the rotary and stepover across the axis. This is not necessary but suits my slow moving 4th axis. Keeps feedrates from getting slowed down by my limited 4th axis speed.

Then I run the code through the great free program "Wrapper" written by a forum member. Andrew Emmans.

Set the axis to get converted to degrees, in my case that is "X to A". Set the material depth which is in radius as a negative number. -40mm in this case. And let it convert the code. It can take a while depending on the code file size.

Loaded it all into Mach3 in my case, and cut it. Gcode is generic to most controllers though not all.

As you can see this is a simple shape with no great challenges. Just a basic project to show the method used. Not a great piece of art or even a good piece of wood but it serves the purpose of demonstration.

Next one will be a 3D model that crosses the "Wrap Join". That is a little more challenging. However it is on the router cutting as I write, and is looking good.

Greg
Attachments
RoseWrap.jpg
MatSetup.jpg
Wrapper.jpg
Toolpath.jpg
WoodRose1.jpg
WoodRose2.jpg
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Re: Aspire and a 4th axis

Postby RoutnAbout » Wed Sep 02, 2009 3:29 am

Fantastic Job Greg,

Guess I should have kept my Indexer. :(
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Re: Aspire and a 4th axis

Postby Fleming » Wed Sep 02, 2009 3:30 am

Glad to see this discussion as I have also played with 4th axis. One confusion I have is why the need to convert to degrees? I have wrapped text around a cylinder by simply defining the Y axis size as the a long scroll and tilting the text to a slight angle. Worked fine. Please explain what is gained by using the degree function.

Thanks.
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Re: Aspire and a 4th axis

Postby metalworkz » Wed Sep 02, 2009 3:35 am

Hello Greg,

That wrapped rose looks great! I will be waiting to see the next example that is currently cutting. What are you using for your 4th axis? Is it something you have fabricated?
Thanks for the very informative thread!
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Re: Aspire and a 4th axis

Postby ManitobaKeith » Wed Sep 02, 2009 4:01 am

Greg,
First let me say "Nice Rose".

I have been following the other current link as well as the link from the original release of Wrapper by Andrew. Andrew does have a new & much faster version that is not quite ready for release and I doubt it will be freeware, but one never knows. He has been away camping and has not had time to work on the few minor learning opportunities that have presented themselves to him. I wish him much success and great learning.

It does seem like there are a LOT of folks that are VERY interested in the 4th Axis, whether for work or for play and you seem to have a pretty great grasp of what it takes. Please keep us informed. Glad you started this post.

I for one will be looking at Harbor Freight, on my way back from SC, thanks to Viktor and his suggestion of their lathe. Hmmmm he always seems to make suggestions that end up costing me $$$ :lol: :lol: Fortunately I already have a 4 axis controller and 4 - 425 oz motors.
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Re: Aspire and a 4th axis

Postby gravirozo » Wed Sep 02, 2009 4:08 am

hello

greg, it looking really nice...
this is great... looks it's a program... i like the toolpath displaying... more visual, even i know what i will cut

i was thinking too on the overlapping...like 1/8 or 2-3 mm.. makes less work , might no sanding...

if critical the "centering" my suggestion would be, cut a small area on top, indexing 4x90 deg cut same spot, on four side.. and of the result be measured with caliper, we will know where is exactly the tool tip... this is the method as raw material can be positioned... to set tooltip visually to a center... gives no exact result..

fleming if you have experience with this, then you can post it... more opinion will take forward this question...

actually i working on making models... they might not affordable... but the method to generating models that is interesting...

greg wrote
---------------------------------------------
There are many big dollar CAM programs that will do all the bells and whistles but many like me have no intention of selling their offspring to pay for it.
-----------------------------


yes greg, this is the main point of this, personally me, before vectric programs, i used more kind.... with these, i think we can solve all need us...


if there's second, or third tool... aspire can generate on small spot 3d toolpath, with a circle like 1/4 dia... and with this toolpath already we can find the exact "zero"

it is really welcomed, if anyone has experience with 4th axis, i mean directly from aspire... should share his experience...

with models i find out some way, in aspire, checking on the "seamless"...
might be to night i can finish one... what i made priorly in cad-cam that works... but the real interesting is to make it in aspire...


thanks
viktor
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Re: Aspire and a 4th axis

Postby Greolt » Wed Sep 02, 2009 4:33 am

For the moment I will just address the point of where to set the Z axis zero.

I don't think any method is tied to zero at the centre of the axis but it makes a lot of sense.

The centre of axis rotation does not change from job to job. It is always constant.

This means that it is easy to establish when changing tools manually. (I have no auto tool changer)

A fixed point on the headstock is what I use to set Z zero. I know the exact offset this point is from axis centre.

It is easily reached for zeroing no matter what stage the job is at or what material has been cut away.

In fact I have the Auto Tool Zero device that I use in Mach, hard coded with that exact offset.

So at initial setup or at subsequent tool change I just jog over to the point on the headstock and run my Auto Tool Zero routine.

If anybody does not know what that is, then make the time to find out. The best accessory you can have on a router, without a doubt.

Greg
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Re: Aspire and a 4th axis

Postby gravirozo » Wed Sep 02, 2009 7:24 am

hello


here's the first try.... it's not the best looking... but the method already works... the amplitudo should be smaller for this dia...
this all made in aspire... this model to mill out without 4th axis.... turn on 4 side...

the lead is 100 mm... so for the four model i have to step this spiral 25-25 mm in aspire..... so it will get new zero... tomorrow i try to cut it... but however i can work on this only after dark... i wrestling a little building 12x12 ... and the rain kept me back...
also i want to finish up an unfolded model.... also a spiralpost... that will work on 4th axis...

for positioning right the patterns on this post, i placed in a prism... which one shows the quarter only of the model...

tomorrow i work on... might be start a better looking...

thanks
viktor


to zeroing a model on rotary i think any point could be... the largest dia looks the simplest...
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01.jpg
02.jpg
03.jpg
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Re: Aspire and a 4th axis

Postby Greolt » Wed Sep 02, 2009 11:23 am

This example ramps the idea a bit further and wraps a 3D pattern all the way around.

The trick is to get the join (all wrapping has to have a join) to line up with no visible clue to where that join is.

It is a geometrical pattern and being shapes created from repeating vector lines it is not so difficult to get the repeat point to fall exactly on the join.

Working on a 80mm diameter again, that gives me a 251.328 length and scaled the repeating pattern to fall on that length.

Aspire produced the gcode and again I used "Wrapper" to convert the X axis to degrees.

A great little program, Wrapper. That is good news that a new version is on the way.

Here is a short youtube of this cutting with a glimpse of my 4th axis for those who asked about it.

Greg

http://www.youtube.com/watch?v=6WWKN7C31e4
Attachments
WeaveWrap.jpg
WeaveCarved.jpg
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Re: Aspire and a 4th axis

Postby Greolt » Wed Sep 02, 2009 1:03 pm

Fleming wrote: One confusion I have is why the need to convert to degrees? ............ Please explain what is gained by using the degree function.


You will find that there are different opinions about this. Because you asked I will give mine and the reasons for it.

I use Mach3 as my controller. Mach will adjust blended feedrate as the diameter of cutting changes across the job.

So during a gcode run if the cutting goes from 50mm diameter to 150mm diameter then Mach will adjust the blended feedrate to keep the actual feedrate the same. All within max velocity settings of course.

If we tell Mach that the rotary axis is just a linear axis we then loose this capability.

My 4th axis has small amount of backlash. For backlash compensation, if the cutting is at 10mm dia or 1000mm dia, using degrees then it stays true all the time because the amount of backlash compensation is in degrees, not a linear measurement

When I call my "A" axis "Y" or "X" I must also adjust the velocity and acceleration settings or things will grind to a halt at the first rapid move.

The most compelling reason to my mind is "WHY NOT". Degrees is the industry standard way of using a rotary axis.

Any other CAM software that we might use will do all rotary moves in degrees. Any other tasks we use a rotary axis for will be in degrees.

And Most of all because it is dead easy.

If we know that a wrapped job is going to be 100mm diameter then we know that 100 x Pi = 314.159 which is the circumfrence.

360 / 314.159 = 1.1459 so every position of the axis we want to wrap in the gcode gets multiplied by 1.1459 (or gets changed to degrees) and the designator gets changed to "A"

If I did that with a calculator I would very quickly get sick of it, but we have computers that can do this very easily and quickly.

Hence the "Wrapper" program. Dead simple. No swapping axis definitions. No resetting velocity and acceleration settings. No getting confused "Which is Y axis now?"

As I said you will hear other opinions. Degrees all the way for me. Just makes sense. :D

Greg
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Re: Aspire and a 4th axis

Postby rgoldner » Wed Sep 02, 2009 4:56 pm

gravirozo wrote:hello


here's the first try.... it's not the best looking... but the method already works... the amplitudo should be smaller for this dia...
this all made in aspire... this model to mill out without 4th axis.... turn on 4 side...

the lead is 100 mm... so for the four model i have to step this spiral 25-25 mm in aspire..... so it will get new zero... tomorrow i try to cut it... but however i can work on this only after dark... i wrestling a little building 12x12 ... and the rain kept me back...
also i want to finish up an unfolded model.... also a spiralpost... that will work on 4th axis...

for positioning right the patterns on this post, i placed in a prism... which one shows the quarter only of the model...

tomorrow i work on... might be start a better looking...

thanks
viktor


to zeroing a model on rotary i think any point could be... the largest dia looks the simplest...


Nice spiral. My Indexer Wizards makes this very easy as a spiral wizard is included. Here's a picture of a hollow and a rope spiral done with the Indexer Wizards.
Attachments
Spirals.jpg
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Re: Aspire and a 4th axis

Postby Fleming » Wed Sep 02, 2009 7:40 pm

Greolt - Many thanks for the explanation about using degrees instead of circumference - that makes sense! I admire the beautiful work that you and rgoldner are doing with your fourth axis :D and look forward to finishing my build of Joe's Hybird so I can rebuild and install my 4th axis (which is based on a $100 mini lathe)! Now if we could just convince someone (VECTRIC :) ) to give us "off-axis" carving such as a caribole leg we shall be in carving heaven :wink: .
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Re: Aspire and a 4th axis

Postby gravirozo » Wed Sep 02, 2009 10:08 pm

THE PHOTOS ARE FOR ILLUSTRATION I'M NOT INTENDING TO COPY THESE...


hello all


the picture i posted i think mislead you all... i have no plan to making posts which one can be made with "spiraltoolpath"....
aspire is a great program, but to generate a spiral, which one easy in cadcam in aspire very adventorous,,,

back in the 80's in europe was very popular the twisted oak post on furnitures... with my friend we converted an old lathe as the "sleigh" or support ? (english is hard) was modified, as the handwheel drove a conegearpair, and this gear trough on a rod drove the spindle... where's the cutters in normal situation we put a bearighouse with shaft and put in homemade "endmills" a 16mm slotted shank was welde on a 5x32 mm hss plate... as we sharpened by hand...

truogh on gears we could change the lead, also an indexrplate was put in the link so we could divide 3-4-5-6 12...

what is on the picture rgoldner posted, the ropetwist need a parabolic shaped bit...
and the lead very critical for this...
for other sample we used 2 bit the fist was a short endmill together with the radisu... and a second was used for the flutes... this second has a short edge only on the front, because after it's cut trough the material, releasing the three "shaft" on the piece... by resonance the part can get damage...
also this secon sample we made only with 3-5-7 opening... and trough on the slot with endmill we could worked off the backside of "shafts"... eventually sanded by hand close to rounded...

the sample i posted, as i gave in my post i want to put on models... like grapes and other motifs, patterns...

dear rich, i would like to make architectural carvings... and indexer can not help my work...
i have checked your wizard...

very great, works even without aspire..
i post some samples, i try to make similar models... they can be cut with or without indexer...
the spiral i posted... it only a base to place grapes, patterns... another difficulties they might have 6-10 inch lead... with your program, i have to use a profiletool... and i couldnot figure out a 8-10 inch diameter endmill could work in a router...


thanks
viktor

on the first picture i made with cadcam... i want to make it wiith aspire...
on the second a grape post for sample... some similar i would like to make...
on the third a post with capital... the capital i plan to model and made from four side might be the corners require four other dividing...
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cadcam.jpg
grape column.jpg
column with top.jpg
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Re: Aspire and a 4th axis

Postby cabnet636 » Thu Sep 03, 2009 1:07 am

Someday you guy's will spin me around and we will

DANCE
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Re: Aspire and a 4th axis

Postby moto633 » Thu Sep 03, 2009 3:11 am

Greg, what are your mach settings to get that quick feed rate? I have been trying to up my 3d carving speeds and your video seems to not slow down much for accell/decell any input would be great. I am picking up an old lathe this week to convert into a 4th axis so I can join in on the fun!!!!!

Thanks,
Nick
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