Pimping the mini-lathe

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16 Aug 2020 13:54 #178406 by rodw
Replied by rodw on topic Pimping the mini-lathe
Well I heard you guys but the dude's comments made me stay up past midnight to watch that video. So you are all in trouble!

I much prefer a perfectly rounded apple pi ove trigonometry any day.

I noticed you used Onshape but then coded the gcode by hand. A friend uses it all the time and subscribed to Fusion 360 just for the CAM side. DO yo have a CAM solution?

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16 Aug 2020 14:14 #178408 by RotarySMP
Replied by RotarySMP on topic Pimping the mini-lathe
Hi Rod,

Well I heard you guys but the dude's comments made me stay up past midnight to watch that video. So you are all in trouble!


Since Rod is from NZ's west island, he can be a little grumpy at times :)

At the start of this weeks nonsensical filming, I assumed LinuxCNC could cut a tapered thread with it's G76. Was kind of committed by the time Andy informed me that the code was never finished, and I had to switch to G33. Gven the number hours it took to write and debug this code, I could have probably learnt Fusion..
;Weird thread
;Why? Because a CNC lathe can!

;Tapered 3 start RH thread 23/57"OD  x Pi TPcm, 11/7 Chi long, with a 23/19e taper angle.
;Z0 is end of stock.

#<_pi> = 3.2654
#<_e>  = 2.71828
#<_chi>= 30.3

#<_starts>           = 3
#<_OD>               = [23/57*25.4]
#<_Z_LeadIn>         = [#<_pi>*4]
#<_Pitch>            = [#<_pi>]
#<_ThreadDepth>      = [#<_pi> /3 ]
#<_ThreadLength>     =-[#<_chi>*11/7]
#<_TaperAngle>       = [23/19*#<_e>] 
#<_NumThreadPasses>  = ROUND[#<_ThreadDepth>/0.1]

#<_SmallDia>         = [#<_OD> - [SIN[#<_TaperAngle>*2]] *[#<_Z_LeadIn> + ABS[ #<_ThreadLength>]]]
#<_DiaChange>        = [#<_OD> - #<_SmallDia>]
#<_NumCuttingPasses> = ROUND[#<_DiaChange>]

#<_feedrate>         = 200
#<_Speed>            = 300
#1                   = 1 ; Index start passes
#2                   = 1 ; Index threading passes
#3                   = 1 ; Index cutting passes

O110 sub ;Cut taper
	O110 while [#3 LE #<_NumCuttingPasses>]
		G0 Z[#<_Z_LeadIn>]
	   	   X[#<_SmallDia> + [[#<_NumCuttingPasses> - #3] * [#<_DiaChange> / #<_NumCuttingPasses> ]]]
		G01 Z[#<_ThreadLength>] X[#<_OD> + [[#<_NumCuttingPasses> - #3] * [#<_DiaChange> / #<_NumCuttingPasses> ]]] F#<_Feedrate>
		G0 X[#<_OD> + #<_DiaChange>]
		#3 = [#3 +1]
	O110 Endwhile
O110 endsub

O111 sub ; Cut Thread

	O100 while [#1 LE #<_starts>]
		O101 while [#2 LE#<_NumThreadPasses>]
			G0 Z[#<_Z_LeadIn> + [[#1 - 1] * [#<_Pitch>/#<_starts>]]]
	   	   	   X[#<_SmallDia> - [[#2]*[#<_ThreadDepth> / #<_NumThreadPasses> ]]]
			G33 Z[#<_ThreadLength>]  X[#<_OD> - [[#2 - 1] * [#<_ThreadDepth>/ #<_NumThreadPasses> ]]] K#<_Pitch> 
			G0 X[#<_OD> + #<_DiaChange>]
        		#2 = [#2 + 1]
			
		O101 endwhile
		M5
		G4 P2
		M3 
		G4 P2
		#2 =1
		#1 = [#1 +1]
                #<_SmallDia> = [#<_SmallDia> - [SIN[#<_TaperAngle>]*[#1 -1] * [#<_Pitch>/#<_starts>]]]
	O100 EndWhile	
O111 endsub

;Main
G18 G21 G40 G49 G54 G80 G94 G90 G7
F#<_Feedrate> S#<_Speed>
M3
G4 P2
O110 call
M5
G4 P2
M3
O111 call
M9 M5 
M2

I have an ancient copy of FeatureCam, to make milling tool paths. Back when I I first converted the Minilathe years ago, it used turboCNC which had a pretty cool G77 canned cycle for facing and turning simple parts, which is really 90 of lathe work. I am going to install Andy's lathe macro's on the lathe, and NativeCam on the mill and see how far they get me. I have subscribed to Fusion, but and pretty experienced with Catia for complex jobs and Onshape for quick things, that I havent found the time to learn Fusion yet.

Mark
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16 Aug 2020 20:47 #178427 by rodw
Replied by rodw on topic Pimping the mini-lathe
F360 is new to me but I bought a 3 year subscription recently while it was half price. I must say I really struggle with it. With my plasma machine all I need is a DXF which I run through Sheetcam. Maybe one day I will have a mill turn machine to make one part. Then I'll need CAM. If I buy it by 31 Dec I can get 100% tax writeoff.... So you just never know.

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17 Aug 2020 16:16 #178486 by RotarySMP
Replied by RotarySMP on topic Pimping the mini-lathe
One thing I like about onshape is that it is wholely cloud based. Before corona I travelled reasonably often for work, and could use evenings in the hotel to design in Onshape on my work laptop which I cant install software on, rather bringing my private laptop as well, just for Catia.
Mark
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17 Aug 2020 19:33 #178518 by RotarySMP
Replied by RotarySMP on topic Pimping the mini-lathe
I have the spindle working, by jumpering the whole closed loop part of the HAL with:
net spindle-vel-cmd-rpm-abs => hm2_7i96.0.pwmgen.00.value

The encoder is also working working. The HAL/INI was largely a PNCConf build.

I can't really get my head around what to do to get closed loop spindle control working, with the gear change.

I figure I need to add a micro switch to my gear lever to report back gear Hi/Lo to LinuxCNC as switch On/Off (I can similate that to get started), but get lost in the signal chain of this HAL as to where to net the commanded spindle speed, where to connect the gear switch, and how to connect hm2_7i96.0.pwmgen.00.value to the resulting output.

I have read through this thread a couple of times, but still get confused.
forum.linuxcnc.org/38-general-linuxcnc-q...-0-10v-analog#177085

I would appreciate any pointer as to the changes I need in the attached HAL. Thanks.
Mark
Attachments:

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19 Aug 2020 09:56 #178693 by snowgoer540
Replied by snowgoer540 on topic Pimping the mini-lathe

rodw wrote: F360 is new to me but I bought a 3 year subscription recently while it was half price. I must say I really struggle with it. With my plasma machine all I need is a DXF which I run through Sheetcam. Maybe one day I will have a mill turn machine to make one part. Then I'll need CAM. If I buy it by 31 Dec I can get 100% tax writeoff.... So you just never know.


Have you watched any of John Saunder's videos on Youtube (NYC CNC)? He has a TON of videos to make fusion simpler. Albeit, most of his videos are mill related, he does have some lathe related ones as well. His videos helped me immensely when I was learning.
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19 Aug 2020 10:12 #178695 by rodw
Replied by rodw on topic Pimping the mini-lathe

snowgoer540 wrote:

rodw wrote: F360 is new to me but I bought a 3 year subscription recently while it was half price. I must say I really struggle with it. With my plasma machine all I need is a DXF which I run through Sheetcam. Maybe one day I will have a mill turn machine to make one part. Then I'll need CAM. If I buy it by 31 Dec I can get 100% tax writeoff.... So you just never know.


Have you watched any of John Saunder's videos on Youtube (NYC CNC)? He has a TON of videos to make fusion simpler. Albeit, most of his videos are mill related, he does have some lathe related ones as well. His videos helped me immensely when I was learning.


Yeh, he annoys me. He makes Fusion look so easy!

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30 Aug 2020 10:34 #180050 by RotarySMP
Replied by RotarySMP on topic Pimping the mini-lathe
Episode 28 is up:


Enjoy,
Mark
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30 Aug 2020 11:53 #180059 by samuelt
Replied by samuelt on topic Pimping the mini-lathe
I really like your videos!

That keypad you found, does it have any identifying markings?
Have been looking for something similar for a while.

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30 Aug 2020 12:25 #180061 by machinedude
Replied by machinedude on topic Pimping the mini-lathe
with 3D tool paths with a ball nose endmill the depth of cut and step over have a lot to do with the surface finish. the small light cuts with a small step over give you a better finish but add cycle time. so it boils down to how good of a finish you want vs the time to get to that finish you want to spend on the part.

one other tip is the bigger the radius the better you can do with finish on your 3D tool paths. but i would stick to the max your machine can handle well. machine rigidity comes into play too.

nice job regardless.
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