Hello Guest it is March 29, 2024, 11:52:52 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - derekbpcnc

Pages: « 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 »
121
General Mach Discussion / Re: Whose Fault Is ThIs?
« on: November 30, 2009, 05:30:57 PM »
Hi,

I have seen the same problem when machining parts with retainer "tabs"
The X & Y accellerations are very different to the Z, as the Z is a driven knee.

If I am feeding x and y at say 300mm per min, the knee tries to do the same if the tabs ramp at 45degs. (Max Z is 250mm/min)
So I have to limit the angle of the tabs so that the Z axis does not "overspeed".

I don't see this as a Mach fault as when the Z moves Mach would need to limit the X & Y feeds to match the maximum acc / vel of the knee.
So I either speed up the knee or fit a Z on the quill....or buy a VMC ;D

ATB
Deker

122
General Mach Discussion / Re: Replicating Parts
« on: November 15, 2009, 12:44:52 PM »
I have a part that uses 25 toolpaths. I designed it in Aspire and would now like to cut multiple parts from a single sheet of material. I don't want to have to redo all of the toolpaths in Aspire when I replicate the parts onto the sheet. Is there any way in Mach to load a g-code file and then tell Mach to run i multiple times at differnet x and y offsets?

I do the same thing. 1 "program" that is called 10 times to give me 10 parts at different locations.
I use the work offset table to program the location of the X and Y offset and call each of the offsets.

ATB
Deker



123
Hmm...tid bit for thought,
Flip the internal cutter upside down, thread to the back side of the bore ( you can see what is happening), use the code out of the threading wizard as if it was an external thread ( of course change for internal thread dimensions ).  ???
RICH

Hi Rich,

My head hurts, upside down, back to front AND inside out :-) :-)
I'll try an external thread first, learn to crawl first and all that ;-)

As soon as I have an update, I'll post my efforts.

ATB
Derek

124
I haven't done much internal threading. Can get away with tapping most of the time......
Shouldn't have any problem. You may want to try just an external thread thread first to gain some experience and see how it goes. Don't know if your lathe is punney or robust.

The big difference to CNC, is that with a manual lathe, you can always adjust the depth cut , ie; some brass will work harden, to suite how things are going.
Let us know how you do,
BTW, why not hang on for say a week  if you can, and waite for the improved version of the threading to be posted.
RICH
Hi Rich,

The lathe worked fine with the old Anilam control - not bad for something fron the 1980s.
A M20 thread is I think the small end of its capability.. 5Kw spindle and about 1 to 1.5kw axis servos.

I'll def get the external threading set up first, I better crack on and get the slotted disc and sensor fitted !

ATB
Derek

125
Derek,

BTW, there will be something posted in the Members Docs on threading using MACH3 Turn. It will cover a lot of territory and is in the making.
Is there some kind of specific threading / cutting that you are interested in or have concerns about?

RICH
Hi Rich,

Thanks for te reply,

I have no specific concerns but having recently converted my Colchester / Anilam lathe to Mach, I now need to get the screw cutting working.
First job will be a M20 x 15 long internal thread in Ali and brass..

The massive post on screw cutting problems makes interesting reading, so I guess I want to set up the spindle feedback in such a way to be "compatible" with the final findings you and Art are working on.

Thanks
Derek

126
TJ,
I also only use a single index pulse. That is what i would suggest you use at this time.
We have been, and continue, to test a number of different impulse combinations, but
nothing has proven to an be advantage at this time or is implemented strickly for testing purposes.

RICH  

Hi Rich,

I've been searching the forum for teh answer to this question...so one slot it is.
re: the slot width, should I use the calculation in the lathe manual, or have you used another "formula"

I guess the main thing is that the slot is not too narrow.

ATB
Derek


127
General Mach Discussion / Re: Duplomatic turret for Colchester
« on: September 13, 2009, 03:52:58 AM »
Hi Hood /Peter,

The small Mitsubishi FX PLCs don't support Modbus (RS232/485 only)

So my choice is use the FX with Pokeys - I need a pokeys for addition switches anyway and talk to the turret PLC by 4/5 descrete Pokeys I/O lines.

Or - use a Modbus capable PLC for a neater installation with much of the M6 macro work already available.
What manufacture of PLC would you recommend? Is the programming software cheap or free :D

I am comming round to the idea of ModBUS.

ATB
Derek.

128
General Mach Discussion / Re: Duplomatic turret for Colchester
« on: September 12, 2009, 08:38:40 AM »
Sounds like it works in exactly the same manner as the one I did the ladder for, all works with timings in the PLC ladder.
 Do you have a PLC already or are you going to be getting one?

 I just got a turret off a Bullard lathe that I am adapting to fit in place of the front post on my Computurn. At the moment its a hydraulic motor that rotates it via a very nice setup of hard rubber worm and it indexes nicely but I am thinking of changing that out to a servo.

Hi Hood,

I will use a small Mitsubushi FX plc - used quie a few of these and might be able to pull one out of some old kit.
I have not done any work with modbus and quite like the idea of being able to test the "coms" between mach and turret by looking at the PLC IP LEDs.
Also, if necessary it will make it easier to transfer to another lathe if I ever had the need to.
Duplo sent me the tech manual with the wiring diagram and timing chart -The motor is a little 3ph jobbie and will need to be conected to a small VFD as I only have 1ph in "my shop".

I'd like to see your 2 turrets in operation when you have it all fitted.

ATB
Derek


129
General Mach Discussion / Duplomatic turret for Colchester
« on: September 12, 2009, 05:03:27 AM »
Hi All,

Here is a photo of the 8 stn tool turret that will be fitted to my Colchester / Mach3 combo.
Turrethttp://img43.imageshack.us/img43/338/img6584s.jpg
Lathe http://img42.imageshack.us/img42/9465/img6551.jpg
The intention is to control the turret function by a small PLC and command the PLC using descrete IO from a Pokeys IO expansion board.

ie 3 outputs from Pokeys to select the tool and an I/p to say tool in position + 1 or 2 fault signals.

The turret has a solenoid shot pin for " rough" positioning.
Clamp lock for holding the turret in accurate position.
Motor rotate CW
Motor rotate CCW
Motor brake
Motor over temp sensor
Solenoide position sensor
Clamp lock position sensor
Turret position sensor (4 binary ops)

So there is a fair bit going on.
More photos of the control build as and when
ATB
Derek

130
General Mach Discussion / Re: Lathe spindle brake
« on: September 10, 2009, 12:37:31 PM »
The auto changer will make a huge difference, I couldnt imagine using my lathe without it ( or should I say them ;) )
 I dont have it yet but I am getting another turret from my friend who is scrapping a bullard lathe, I will replace the front toolpost so I will end up with front and rear turrets :)

Hood

Hi Hood / Blue Pin'

I think I will try controlling the brake via the VFD... although it is disconnected at the moment and the VFD is not complaining.

Picked up a tool turret this week. 8 position Duplomatic. I will make a small PLC control for this and select the tool number using I/O from a Pokeys expansion board.
Duplomatic sent me a pdf of the tech manual - the wiring looks simple enough.

I'l post a few picks on a new thread .
ATB
Dekre.

Pages: « 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 »