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Mach Discussion => General Mach Discussion => Topic started by: bwprice100 on July 15, 2010, 03:03:39 AM

Title: True 4 axis milling
Post by: bwprice100 on July 15, 2010, 03:03:39 AM
Hi All

Just a quick question (so much to learn)

I am just starting to get my 4 axis mill conversion up and running and I have started to use MeshCam to do some programming. Now it is is a very good program but it only seems to use the 4 axis to rotate the part before continuing with machining using the X,Y&Z i.e. no machining is done while the Rotary axis is moving.

The question is does anyone have examples of Mach3 machining with all 4 axis (3 linear and 1 rotary) moving and what CAM package did they use for this?

Thanks Brian
Title: Re: True 4 axis milling
Post by: Tweakie.CNC on July 15, 2010, 05:33:36 AM
Hi Brian,

I think it's all related to the price you are willing to pay for the software.

'MeshCam' uses an indexed 4th axis toolpath and is very well priced whereas 'DeskProto' will allow the 4th axis rotation machining you mention but at a higher price.
(As with MC the DP software is available for limited trial so you can see if it will do the job you require before you buy).

Moving up in price 'Visual Mill' will also allow 4 axis simultaneous operation.

There are lots more out there but these are just the ones I have tried and used.

Tweakie.
Title: Re: True 4 axis milling
Post by: bwprice100 on July 15, 2010, 08:00:52 AM
Thanks for that.

It's just for the future and knowing what I might need if I meet a limitation with MeshCAM

Brian
Title: Re: True 4 axis milling
Post by: Tweakie.CNC on July 15, 2010, 08:33:17 AM
Brian,

I have never found the need (yet) for more than 3 Axis at any one time and I am sure that with a bit of planning that is all that may be required. So It may not be a bad thing to stick with MC and save yourself a lot of, perhaps unnecessary, dosh.  ;)

Tweakie.
Title: Re: True 4 axis milling
Post by: ger21 on July 15, 2010, 11:59:59 AM
DeskProto is running a special for hobbiests at a greatly reduced price. When I get a 4th axis running, I'll be pressuring for Robert to add continuous 4th axis to MeshCAM. :) But I wouldn't count on it anytime soon.
Title: Re: True 4 axis milling
Post by: xaco on July 19, 2010, 04:33:30 AM
hi,i was in same situation as you when i bought MeshCAM,its great softwer for that  money but does only indexing as u mentioned...now i try to use ArtCAM for 4th axis,my other options were   MadCAM (if u use Rhinoceros) and DeskProto
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 10:42:31 AM
ArtCAM, Deskproto, VisualCAM are not true 4th axis programs.. They always generated gcode for 3-axes...
Title: Re: True 4 axis milling
Post by: bwprice100 on July 19, 2010, 11:36:56 AM
ArtCAM, Deskproto, VisualCAM are not true 4th axis programs.. They always generated gcode for 3-axes...

Meshcam generates code for the 4th axis, the point is it will not generate code so that all 4 axis can be moving at the same time. Or is this not what you are saying?

The main reason for my question is so I can be a bit ahead with my planning. I have a possible requirement to reproduce small complex casting by milling from solid. As it stands at the moment it would seem Meshcam can cope with this but will I need a more sophisticated Cam package in the future, perhaps for speed or smother finished.
I will probably look at bit closer at 'DeskProto Full'

As I am new to Gcode programming what would a simple piece of Gcode look like that would have all 4 axis moving together in a non linear way; for that matter I don’t think I could do it in 3 axis. :)

Brian
Title: Re: True 4 axis milling
Post by: docltf on July 19, 2010, 12:31:01 PM
just type out a line of code.

g1 x-.655 y.165 z-.060 a15 f5.0

that is all 4 going at once,pretty simple.
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 12:42:03 PM

Meshcam generates code for the 4th axis, the point is it will not generate code so that all 4 axis can be moving at the same time. Or is this not what you are saying?
Yes..Meshcam generate Gcode for 4th axis..but it is not true 4th axis..You are canabilizing one axis into Rotary motion...
The Gcode for true 4th axis is
g1 x-.655 y.165 z-.060 a15 f5.0
whereas Artcam,Meshcam and Deskproto will generate like
g1 x-.655 y.165 a15 f5.0



The main reason for my question is so I can be a bit ahead with my planning. I have a possible requirement to reproduce small complex casting by milling from solid. As it stands at the moment it would seem Meshcam can cope with this but will I need a more sophisticated Cam package in the future, perhaps for speed or smother finished.

I will probably look at bit closer at 'DeskProto Full'

Depends on the accuracy you needed... Some software only work with STL models and those STL models are not accurate representation of 3D models...  Deskproto or VisualMill will work for you... The VisualMill will be much better as it has Feature machining capabilities..

As I am new to Gcode programming what would a simple piece of Gcode look like that would have all 4 axis moving together in a non linear way; for that matter I don’t think I could do it in 3 axis. :)

Brian

See my simple 4th axis..its not a true 4th axis , i generate Gcode with Artcam
www.my-woodcarving.blogspot.com
Title: Re: True 4 axis milling
Post by: docltf on July 19, 2010, 12:57:37 PM
nice site Khalid.

bill
Title: Re: True 4 axis milling
Post by: bwprice100 on July 19, 2010, 01:07:40 PM
just type out a line of code.

g1 x-.655 y.165 z-.060 a15 f5.0

that is all 4 going at once,pretty simple.

Yes but not non linear. What would the code looke like to get the cutter, for example, to move in a simple arc at an angle that is not normal to any axis?

Brian
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 01:35:52 PM
He showed you simple 4th axis code... The complex true 4th axis code can be generated Via true 4th axis software only;)
Title: Re: True 4 axis milling
Post by: bwprice100 on July 19, 2010, 01:45:39 PM
He showed you simple 4th axis code... The complex true 4th axis code can be generated Via true 4th axis software only;)

Yes but my original question was for non linear code not linear code which i am aware of. Sorry if I am using the wrong terminology.

Brian
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 01:49:51 PM
the codes are subsequent lines with discrete movement in X/Y and Z-axis so you will get non-linearity out of linear codes..
or just read this thread
http://www.machsupport.com/forum/index.php?action=printpage;topic=14288.0
Title: Re: True 4 axis milling
Post by: docltf on July 19, 2010, 02:00:52 PM
if you move X & Y at the same time you are moving in a plane not linear.


bill
Title: Re: True 4 axis milling
Post by: bwprice100 on July 19, 2010, 03:04:25 PM
if you move X & Y at the same time you are moving in a plane not linear.


bill


Hi Bill

My interpretation is that the axis are moving in such a way that they generate a straight line between 2 point (linear), that straight line may be at an angle to all three axis but it is still the machines attempt at moving in a straight line.

For example this code from previous post
g1 x-.655 y.165 z-.060 a15 f5.0

Is still generating a linear interpolation it is only the fact that the A axis is a rotary axis that you get a non linear path and that IMHO is not the code doing this but the mechanical attribute of the rotary table; the same way a lathe generates a cylinder from a single point cutting tool and a linear movement.

Where as the code below does seem to be generating a non linear path that is non reliant on the mechanical generation of the path. The only caveat is that it is not using the 4th axis and the axis of rotation must be in a normal relationship to either the X, Y, or Z axis.
==============
G0 G49 G40  G17 G80 G50 G90
M6 T0 (TOOL DIA. 10)
G21 (mm)
M03 S0
G64
G00 G43 H0  Z1
X14.5 Y-5.75
G00 Z-2
G01 G42 P5 X8.75 F30
G02 X3 Y0 R5.75
G03 X-3 Y0 R3 Z-1.5
G03 X3 Y0 R3 Z-1
G03 X-3 Y0 R3 Z-0.5
G03 X3 Y0 R3 Z0
G03 X-3 Y0 R3 Z0.5
G02 X-8.75 Y-5.75 R5.75
G01 G40 X-14.5
G00 Z1
M5 M9
M30
=============

Are my conclusions correct?

Brian
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 03:09:06 PM
G03 and G02 are circular interpolation so they are not straight line:) these moves can only be taken into Plane.. so for a true 3D the interpolation is very difficult... and the softwares are very costly..
Title: Re: True 4 axis milling
Post by: bwprice100 on July 19, 2010, 03:15:10 PM
G03 and G02 are circular interpolation so they are not straight line:) these moves can only be taken into Plane.. so for a true 3D the interpolation is very difficult... and the softwares are very costly..

Cheers for the response.:)

As refinement to my original post what software can do this?

Brian
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 03:19:30 PM
My answer is simple..I don't know..I am also after this type of software...
Just check EdgeCam, Mastercam, GibbsCam.. i think they have a true 4th axis capabilities...
Title: Re: True 4 axis milling
Post by: docltf on July 19, 2010, 03:39:11 PM
you can take a look at this freeware called - cnc toolkit - .it is a pain to sign up for but it is free.
might be what you need to get going.they work on it all the time.

bill
Title: Re: True 4 axis milling
Post by: khalid on July 19, 2010, 03:53:29 PM
Yaa i have seen it and worked with it..but it is difficult;)
Title: Re: True 4 axis milling
Post by: docltf on July 19, 2010, 06:03:19 PM
it might not be that bad for brian since he is new at this.he will take a few lumps up front learning the package.but in the
longrun he might come out ahead of the curve.they add to it every week and it has plenty of options.the stuff it can import
is pretty impressive.

bill
Title: Re: True 4 axis milling
Post by: BR549 on July 20, 2010, 12:19:20 AM
To do what you want to do it takes 5 axis not 4 (;-)

4th axis work is basically 3 axis WORK as IF you move the spindle OFFcenterline of the rotary then your cutting is offset from the rotary axis  and difficult to do and mostly NOT neccesary as you will get the same results from just the 3

Just a thought,(;-)

Title: Re: True 4 axis milling
Post by: khalid on July 20, 2010, 12:40:14 AM
A little apprehension on this "4th axis work is basically 3 axis WORK "..
A true 4th axis work is actual 4th axis work includes simultaneous movements of all 4-axis...
Title: Re: True 4 axis milling
Post by: BR549 on July 20, 2010, 07:48:15 PM
MUMMMM don't think so(;-), Think about the relationship of all 4 axis. ONE of the XY axis has to remain on the rotary axis centerline to make cutting senseable. AND you gain nothing by moving off of it.

Now IF you are 3 axis plus 4th indexing then you have 3 1/2axis control. But cutting is still 3 axis. Even 3d 4th is still 3 axis movement. Maybe a 4 axis where the 4th is atrunnion on the spindle. But never saw one that did not have the 5th as well.

I don't every recall seeing a true 4 axis machine that was not a 5 axis control. But I could be wrong. (;-)
Title: Re: True 4 axis milling
Post by: docltf on July 20, 2010, 09:12:43 PM
BR549

i do a 4 axis part that has to move off the centerline of x & y in order for it to work.
XYZA all have to be in motion to make the cut.it is a pretty neat looking cut when it is
finished.when you look down the nose it looks like the bow of a boat.


bill
Title: Re: True 4 axis milling
Post by: BR549 on July 20, 2010, 10:24:10 PM
It would be interesting to see a picture of your setup.
Title: Re: True 4 axis milling
Post by: bwprice100 on July 21, 2010, 02:53:36 AM
you can take a look at this freeware called - cnc toolkit - .it is a pain to sign up for but it is free.
might be what you need to get going.they work on it all the time.

bill

Thanks for that Bill, I will look into this.

brian
Title: Re: True 4 axis milling
Post by: bwprice100 on July 21, 2010, 02:58:17 AM
To do what you want to do it takes 5 axis not 4 (;-)

4th axis work is basically 3 axis WORK as IF you move the spindle OFFcenterline of the rotary then your cutting is offset from the rotary axis  and difficult to do and mostly NOT neccesary as you will get the same results from just the 3

Just a thought,(;-)



My rotary 4th axis will be mounted at 90deg to the XY plane and its axis is in line with the X axis. With Meshcam it can only really be used as a convenient way of orientating the stock and as far as I can tell will not move whilst cutting.
Title: Re: True 4 axis milling
Post by: halfmill on November 03, 2017, 04:58:57 PM
Hi True 4th axis milling.  I have your same situation, so I am very interested if a set of answers explaining  things more clearly arrives. I will try and see how g1 x-.655 y.165 z-.060 a15 f5.0 works as suggested.  My issue is that I need 4th axis to turn independently from x-y-z axises...  I think you are saying you have the same issue... so I will watch this more... bob
Title: Re: True 4 axis milling
Post by: halfmill on November 03, 2017, 05:07:12 PM
As far as software goes, no one has mentioned fusion 360 by autodesk.  Now is there something that someone knows about this software that would prevent 4 axis milling... bob
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 01:16:02 AM
You can do continuous 4th axis in Fusion 360 yet, just indexing 3+1 and 3 + 2 and wrap
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 01:22:18 AM
Hi dude1,

Quote
You can do continuous
it that you CAN do continuous or CAN'T do continuous?

Craig
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 01:41:38 AM
Thanks joe, yer can not do continuous yet, teach me for typing as I am waiting for a pattern toolpath to generate sinces fusion and HSM does not have continuous yet only a 170 toolpaths
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 01:58:28 AM
Hi Dude1,
thanks for clearing that up, from the way you are talking is continuous 4 axis coming? I haven't used Fusion much but was pretty impressed all the same,
even 3+1 indexing is pretty damn good, and really hard to complain about the price!!!

I don't have a very high opinion of Autodesk's money gathering policies but with Fusion they have proved me wrong bigtime!

Craig
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 02:12:53 AM
Hi Dude1,
this is my quote:
Quote
Autodesk have a policy...'Bend over with trousers down while we extract the money we want'.

Craig
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 04:01:52 AM
They are long term planning, there are a few companies starting to do it, where students and teachers get it free or realy cheap and hobbyist with some can get the same thing or get the student version, solidworks student edition if you search around you can find it dirt cheap per year I will try and find the link I have for getting it for FA.

cero have one as well for students.

Yep that's why they brought out artcam and Delcam Plc to get the artiey stuff and the 4th axis plus stuff.

Its one day
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 04:06:41 AM
link for solidworks cheap https://www.eaa.org/en/eaa/eaa-membership/eaa-member-benefits/solidworks-resource-center/solidworks-student-design-kit
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 04:18:29 AM
Hi Dude1,
that's very kool indeed. It beggars me that they can be so generous with 'potential' customers but as soon as you express a genuine interest in being an
actual customer do they start grinning and writing down numbers with lots of zeros.

Nonetheless I'll take whatever scraps they are offering.

Craig
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 04:26:53 AM
To properly corner a market they all need to drop the prices and fire the dickheads that work for some of the CAD/CAM companies and get people who know both sides very well.
The tooling companies are the same to many word people with no real background in cad/cam or machining in general, kennametal has started to send all there tooling guys out for a few weeks to learn about machining at a high end job shop and there testing labs.

Yes I have had to many set too with support people lately and rant over.
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 05:03:28 AM
Hi,
one piece of software I use is Eagle a PCB drafting program. When I bought it a perpetual licence was $700NZD. Element14 later sold perpetual licences for the
next generation of the software for $2300NZD. More recently Autodesk have bought it up and they want $500USD annually.

I don't know how the community of users will react to a change to a subscription model and likely to be pretty grumpy at having to log in with Autodesk every
two weeks to keep their program alive.

I suppose if Autodesk brown enough of the current users of then some other company will come up with a program of their own, supply/demand etc.

I feel aggrieved that software just goes out of my reach.

Craig
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 05:45:06 AM
I did not realise that you are a kiwi where about are you if you don't mind me asking you pick looks like the Marlborough sounds
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 05:58:08 AM
Hi dude1,
we have conversed before, the picture is Banks Peninsula east of Christchurch. How have you and yours recovered from the earthquake?
I don't know about you but if the gurus are right and we've had our 1 in 500 year event I'm bloody glad its over.

To others reading this post dude1 was shaken by a sucession of earthquakes reaching something like 7.6 about a year ago.
About 5 years ago we suffered a 6.8 but only 5km deep immediately below the city of Christchurch. Both events did incredible
damage and not inconsiderable loss of life.

Craig
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 06:17:46 AM
More. Than likely I am bad at rembering names yes 7.8 I don't won't to go through that again it nearly killed my wife
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 06:35:26 AM
Hi dude1,
that's sounds scary, was she badly injured?

Its hard to estimate what the earthquake has done to all our thinking...in some respects nothing has changed and in other subtle but powerful ways
there is a fear that lives in us that can't be answered or gainsaid. I am very far from a religious man but I do pray that there is no recurrence.

Craig
Title: Re: True 4 axis milling
Post by: dude1 on November 04, 2017, 04:30:51 PM
A big jewelry box fell off the draws beside her bed and landed on her pillow, she was not in it at the time if she was it would of stoved her head in, everytime I hear a sound similar to what I heared before it hit scares the ********* out of me.
It's amazing how many earth quakes struck with in split seconds of each other they think it was 12 from hammer to ward within a few seconds, at least it was smaller than the last one that hit the same area back the 1800, did you see the report from nasa on how much the ground moved by.
Title: Re: True 4 axis milling
Post by: joeaverage on November 04, 2017, 04:37:51 PM
Hi dude1,
I find it hard to believe the pictures and the numbers about how much things shifted.

I'm several hundred k from the epicentre but I would swear that there was continuous motion for 20 minutes, it seemed to peak and then fade over a few minutes
then another one would come along. Yes the sound is terrifying...

Craig