Hello Guest it is October 23, 2019, 05:35:10 PM

Author Topic: 4th Axis Probing/Diigitising How??  (Read 7640 times)

0 Members and 1 Guest are viewing this topic.

Offline Katoh

*
  •  274 274
    • View Profile
4th Axis Probing/Diigitising How??
« on: April 02, 2009, 10:53:26 PM »
G'Day to all
I'm in the process of setting up my 4th rotary axis up on my router, the rotary axis runs parallel to the Y axis and has a maximum run of 1250mm and Free space of 250mm either side of the center line, While I'm waiting on parts and completing the mechanical side I thought this would be a good time to pick all the brilliant mind's out there on a problem.
The 4th axis will be used to create shotgun stocks based from an original stock, What I am hoping to do is to fix the but side of the stock to the rotary table and leave the rest of the stock free floating as to be able to machine the action reliefs and be able to digitise the original.
Is it possible to use a touch probe in this configuration to digitise the stocks while setup on the rotary axis, the router has a touch probe already installed and works fine but how can I rotate the stock and digitise at the same time. Or is there another method of doing this using video probing or laser? What I need to be able to do is to digitise an original and then be able to alter it or duplicate it.
Any suggestions of what software for altering, and producing code would be much appreciated. I have added some pics of a basic stock so you can see what I'm up against, there is a side view, bottom view, top view and one of the action relief.
Thanks for reading
Katoh
Cheers
Katoh

vmax549

*
Re: 4th Axis Probing/Diigitising How??
« Reply #1 on: April 04, 2009, 10:50:56 AM »
HIY KATOH, Yes you can probe a gunstock with a 4th or without a 4th(;-).

You will have to create a macro to drive mach to do it in a 4th axis senario. Mount your stock as you said with the butt against the mounting plate. Support the free end with a live center to support it.

Then you will center your spindle over the 4 th axis.

Now here is where a program or macro comes in. You have to do this one of several ways.

1 bed of nails approach.   rotated B so one side of the stock is flat on top. Then run a mach probing routine to probe the entire surface.  Rotate the stock 90 deg andf repeat. rotate 90 and repeat rotate 90 and repeat.

this will give you all four sides as separte point clouds . Then you will have to process the points in a 3d program that can deal with points clouds. then process that through a CAM program to generate your machine code to cut. YOu will cut in the same manner cut rotate 90 cut, etc

2  wrap around mode..    This way you need a program(macro) to probe down with z while the B rotates 360 deg then move over a squeak and probe and rotate agin, repeat the length of the stock. This will give you a full points cloud that lays out like a sheet. 

3 same thing only you pbrobe all the way down the long axis rotate a sqeak then probe back, repeat,repeat untill you have rotated around the stock.

You will want to use a fitted plug to slip into the cavity where the stock meets the action to help support the stock blank while cutting. Then you can cut the new stock to fit the action as a separate function.

Also you will want to mount the stock offset so the center line on mounting will line up the free end to the part that will NOT be cut so you can use a live center to support it during cutting. I can supply a drawing of that part if needed.

IF you need help creating a program (macro) to drive mach let us know we can help with that part.

As to working to finish the pointcloud into a cutt program that is not my strong suite(;-).

Hope that helps (;-) TP
« Last Edit: April 04, 2009, 10:56:47 AM by vmax549 »

Offline Katoh

*
  •  274 274
    • View Profile
Re: 4th Axis Probing/Diigitising How??
« Reply #2 on: April 05, 2009, 08:18:24 AM »
Hi vmax549
All I can say is yes to all the above. Firstly thanks for the reply.
Question 1 would you need a live centre on the action end for stability, I'm pretty sure that with some good clamping on the but side you would get minall to no movement on the stock as I'm yet to encounter a stock more than 16' in length. and theres a fair bit of wood on them.
The first way I understand accurately what your describing method 2 and 3 Have got me a little lost in the way they work,.
It would be very much appreciated if you can help me with a macro to do this, what sort of software would be the easiest best for bringing all the point clouds together?
I was trained on Autocad back 22 years ago and have used it ever since but not really in the 3d modelling, I have access to Rhino but have not really had the time sit down and learn it. the problem here is most of this stuff has to be self taught, theres not a big community of CNC people were I am. I believe there is about  8 in my region and all these people do different things to me with there machines then what I do with mine. So you could well imagine when it comes to learing software, we are on a steep learning curve.
Thanks
Katoh
I forgot to mention I'm using one of Arnie Minear's touch probes, will this make a difference to anything?
Cheers
Katoh

vmax549

*
Re: 4th Axis Probing/Diigitising How??
« Reply #3 on: April 05, 2009, 12:12:47 PM »
Using a live center to support the stock is the BEST solution. Because you will need to use it to cut it accurately. So it is best to probe in the same manner you intend to cut it.

The rotary probing is just another  way to do the probing. Does not matter how you gather the points as long as you get all of them or at least most of them.  To use you set up the z in the y centerline. You line probe all the way iY to the end of the stock, rotated the B say .25 deg and probe all the way back to the begining, rotate .25deg probe to the end and rotate and probe back to the beginning.  This way you have a points cloud based on the rotation of Baxis.

Sorry by I am not fluient in any of the 3d cad/cams to help you with that part(;-) I do know people use Rhino alot if that helps.

(;-) TP

Offline Katoh

*
  •  274 274
    • View Profile
Re: 4th Axis Probing/Diigitising How??
« Reply #4 on: April 05, 2009, 06:58:40 PM »
Hi vmax549
OK I got it Know. yes I understand exactly the other method, for the tail stop I could always run a piece of dowel through the centre hole to support not a real drama there. would you recommend using a stand alone point cloud program, I did a bit of google last night on the subject and came across a few programs that took all these [point clouds put them together and then sent them to cad programs for editing.
It would be much appreciated if you could help me with the Macro for Mach, I suppose once you have that working then its just a matter of sending the data from one program to another.
Thanks Again
Katoh
Cheers
Katoh

vmax549

*
Re: 4th Axis Probing/Diigitising How??
« Reply #5 on: April 05, 2009, 09:37:41 PM »
I will work on a probing macro for you (;-)  Let me know when you have your 4th axis working.

(;-) TP

Offline Katoh

*
  •  274 274
    • View Profile
Re: 4th Axis Probing/Diigitising How??
« Reply #6 on: April 05, 2009, 10:52:43 PM »
vmax549
I cant THANKYOU enough for this, is there any way that I can assist you? My table is ordered iand is coming from Overseas I don't expect it till next month some time, but I already have my router set up for it the gecko is  in, all the wiring, mach is setup it just needs to be connected and activated in mach.
Just a little thought as you stated earlier about the 3 different methods of probing is one better than the other, or do they basically come up with the same result in the end.
Thanks
Katoh
Cheers
Katoh

vmax549

*
Re: 4th Axis Probing/Diigitising How??
« Reply #7 on: April 06, 2009, 05:23:01 PM »
YES(;-) they do.  The nice thing about useing the fourth as a rotary the probing routine can run continously till done. AND it will run a LONG time to d the entire stock depending on the feedrate you probe at.

The macro will be progamable as to length width and depth of z, resolution AND feedrate so you can play a bit to find what is comfortable for you and your machine.

(;-) TP

Offline Katoh

*
  •  274 274
    • View Profile
Re: 4th Axis Probing/Diigitising How??
« Reply #8 on: April 06, 2009, 06:57:25 PM »
Sounds Good, I see very clearly now. Would the probing speed be the same as cutting speed? or are feedrates to be determined when all is up and running and were actually probing a stock?
If its cutting feedrates i found my router is most happy at 2500mm/min for X/Y and 1000mm/min in Z that's just a speed that I have found were the whole machine is smoothest and changes direction easiest, ( its hard to explain in words but you can tell were the router is the happiest)
Thanks
Katoh
Cheers
Katoh

Offline Graham Waterworth

*
  • *
  •  1,890 1,890
  • Yorkshire Dales, England
    • View Profile
Re: 4th Axis Probing/Diigitising How??
« Reply #9 on: April 07, 2009, 07:19:39 AM »
I take it you are going to fill all the holes and block in the open end.

Could be costly if the probe shot down the slot.

Graham
Without engineers the world stops