Joseph Noci 1 | 14/12/2021 17:58:26 |
1323 forum posts 1431 photos | Thanks Baz - I am enjoying the building, but it does become a bit much sometimes... John, I suspect my 'code' won't make it anywhere - its is not really universal - the C axis is very specific- using a powerful step/direction servo motor ( not stepper, and not true servo- it is closed loop servo, but closed internal to the motor, with its own servo driver, encoder, etc). The ATC is also unique/specific and so the polar interpolation mode integration is likewise somewhat specific - the math not so, but the glue is rather. The C axis, ATC and a few other bits are Hal compile components, and will never be considered mainstream Linuxcnc code to be integrated into master. Also, a large proportion of the tricks is also all in the INI and HAL files... So, probably not - just another one of those 'brilliant' glitches in life... I admit to not having made progress with a probe setup.. I have only just got to grips with Lcnc's rather cryptic description of how to set up tool offsets...And as the ATC can host 8 tools, I use one master tool (facing roughing tool) , set its offsets accurately once ( painfully) and then set the othesr in reference to the master, also painfully. I need to get the machine done so I can use it and discover how much of a pain it is with future tool setup..A threading, parting, facing/roughing/finishing and triangle tip should cover most simple work without changing tools - the others are drill bits, two fixed boring bars, center drill and live tool. The Polar mode for your laser engraver is good - just be aware of the Atan issue near center - results in rapid rotations of the rotary axis, sometimes 'instantaneous'...Clock face periphery engraving is no problem! There are many polar 3D printers, cheap too, that work like that - a rotary table/disc with a linear arm plus Y axis. Maybe get one of the better ones of that type and hack it? Joe |
Joseph Noci 1 | 14/01/2022 11:51:17 |
1323 forum posts 1431 photos | Progress on the lathe enclosure was somewhat hindered by the holidays - Powder coaters , Perspex suppliers, FESTO piping/stopcock suppliers, LocLine suppliers, etc, all insisted on closing for the holidays... Some have opened, some have supplied and so some progress has been made. Getting close now... The Splash.Swarf enclosure is complete. All the Metalwork is done, painted and together. I used 6mm perpsex for the window ( no sanely priced 'flexicrylic - the non-shatter stuff - available in Southern Africa - R4700.00 for 2.4Mx1.2M, the smallest available) This required a 38degree bend in it, so I mad a supawood jig and heat-bent the perspex with a heat gun. That worked very well. Heat gun heater..
The bent sheet.
Handles fitted and cover located on Enclosure window. I have to split my post into 2 or 3 it says - 1450 words to many - WHAT??? Don't mind this forums software to much, but this gets me every time and it irks me - there are not even 1400 words in the total post...
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Joseph Noci 1 | 14/01/2022 11:55:21 |
1323 forum posts 1431 photos | Next post with simulated brevity... The coolant pump is also done and tested. In a previous post I indicated I would use a neat oil 'coolant'/lubricant - That was not a success. The oil was great, very thin, and does is intended job well, but the mess is intolerable. An oil film sits on everything, and just sits there. It does not run off like the water soluble oil solutions do. It sits on the swarf and takes days to drain of, and even then , not so well. So I dug for a more modern soluble and found some excellent stuff - Ecocool 600-NBF, made by Fuchs. from 4:1 to 20:1 mix, and £45.00 for 20liters. When mixed, the solution is clear and has no detectable smell. Drains off quickly, and left pooled on a shiny machined clean mild steel plate over the Christmas/New year week, left not a mark. The pumps is a 12V fuel injection pump - seems to be able to develop a good few bar pressure. It hangs in the coolant tank with an inlet sieve. The drain from the lathe goes through 2 further sieves on route before the coolant drops into the tank. We will see what the coolant mix does to the pumps gears/seals, etc. The pumps was inexpensive anyway! Coolant spouts placement on a CNC lathe is a big deal..Normally on the CNC machines the coolant spouts from the tool holder onto the cutting edge, often out the cutter itself with special coolant channels in the cutters, drills, and tool changer. Since that is not possible on my setup, I opted for two spouts, one placed for surface and face cutting, and one for drilling and boring and with Live Tool spindle- the latter spout to the right of the workpiece, the former on the left. (some suppliers are STILL on holiday, so the right spout locline has not yet been lengthened..) The left spout is fixed, and will flood fully the workpiece from behind / under. The right spout moves with the carriage and is aimed at the workpiece center face.
Still some machine covers at powder coaters, and when that's done the machine is 'ready' to use... On the software side, My good Wife has modified much about Linuxcnc's basic setup to make a really nice user interface, and with features that make the machine user friendly. I looked at the many 'available' screen MMI options out there for Linuxcnc - some very fancy looking ones, and after detailed investigation decided they are of little use. They tend to be flashy, many buttons and LEDs and options, dozens and dozens..There are 'nice' tools to allow the screens to be easily modified and changed, but likewise, I found that it took days to understand what the creator of that screen had done, what the buttons did, how they tied into Linuxcnc, etc, After writing up a spec of what I wanted on a display, info, buttons, etc, it was clear that these screens were a waste of time they were so much eye-candy, done because the creator could...I bet none of those creators actually ever used one of there creations in a working machine environment! In addition, there are wonderful incompatibilities between the screens ( the language they are written in, Python2) and Linuxcnc Vers2.9, which ONLY works with Python3 addons, etc. Lcnc vers 2.8 is the current 'formal' release, but does not have any of the kinematics and features I need for the C axis / live tool on my lathe. So, My good wife modified the vanilla Linuxcnc AXIS screen definition, down at Python3 level, and we have a very nice screen setup... As soon as the powder coated stuff is back, lathe assembled, etc, videos will happen! On the CAM side, I found a package called KIPWARE : Kipware CAM sofware Which is a conversational CAM tool, works very well, can do my Live tool / C axis with little effort, and allows easy Gcode generation for all basic lathe machining operations. The Company is 'glitzy' and sort of sticks in my throat, the product presentation is also a little garish, but it works and the price is not bad.. That's it for now.
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Joseph Noci 1 | 14/01/2022 12:29:03 |
1323 forum posts 1431 photos | The KIPWARE mentioned was supposed to be a link to the site - I am sure I set it as a link - maybe mods killed it for me, or maybe I was just dreaming when I did it - here it is again....
Kipware conversational lathe CAM
If it turns un-linky again, then I blame the mods... |
Stefan Hertweck | 16/01/2022 18:56:55 |
1 forum posts | Hello Noci, I read this post with high interest. Very impressive work! That also applies to your other previous projects. Also interesting to see what kind of (wildlife) work you do in Namibia. My respect. Greetings from Germany, Stefan. |
Pete. | 17/01/2022 02:39:36 |
![]() 910 forum posts 303 photos | As usual Joe, your post is hugely impressive, also as usual the electronics is over my head but from my perspective very impressive, lovely sheet metal work on the enclosure it all looks very factory fit, I'm pleased to see you got very nice results with your ad hoc perspex bending methods, I have on the odd occasion looked at perspex heating units but could never justify it for very occasional use, I remember using one in design class at school and have thought on the odd occasion it would be a nice material to make things with, your results have inspired me to have a go with something similar. I also agree with Stefan on the wildlife, there's nothing quite like African wildlife, I remember in the early 90's as a 9 or 10 year old climbing out of the swimming pool at a friends house in Harare and there 12 feet in front of me was a 7 foot Cobra reared up with it's neck flared out staring me straight in the eye, one of the other kids shouted "snake" all of the adults suddenly got very serious, my father having served in the Rhodesian armed forces in the late 70's had taken a course Snake Specialty, I believe everyone had to pick an aspect of bushcraft to specialise in, before I knew it he'd grabbed a broom and garden spade pinned it's head down with the broom and swiftly removed its head with the spade. The gardener was holding the decapitated Snake up on the front garden while my father took a photo, a rotund African lady walked by with two full bags of shopping weighing her down, she looked over saw the gardener (forgive me for forgetting his name I was quite young) holding this huge Cobra and started running down the street screaming, it's one of those images that will be etched into my memory forever. |
Joseph Noci 1 | 23/03/2022 17:08:45 |
1323 forum posts 1431 photos | Not really a continuation of the Lathe itself, but related since I am pursuing touch probing concepts for the Lathe. Most 3D touch probes work on the principal of a lever (the ball attached to the end) moving a tri rod contact from 6 balls, all items electrically in series, so when one rod breaks contact with a ball, the touch probe has made contact. Some DIY attempts have used a Piezo sounder disc attached to the touch probe, and relies on high gain amplifier detecting the voltage spike from the Piezo when the probe 'strikes' the workpiece. These have various measures of success - contact must be 'definite' - slow approaches require very high gain in the amplifier which then requires deep filtering to prevent machine vibration detection etc... I went another route - used a piezo disc, but in a closed loop oscillator so the probe ball tip 'vibrates' ultrasonically. The disc holder is critical - the piezo disc domes in and out during oscillation, so supporting the disc is normally at 2/3 its diameter. I supported it on the periphery at 3 small points, zero deg, 120deg, and very critical, 220 deg, NOT 240deg. 240deg gave a probe tip up/down motion only, almost no side motion. Moving the 3rd support caused the tip to oscillate up/down and circularly, ie, the tip oscillates all over inside a sphere around 0.003mm larger than the ball on the tip...This was measured with a Laser inteferometer at the local Mining Mineral analysis labs..!! The piezo disc is a common buzzer disc, with 3 contacts - GND, main contact and feedback contact. The oscillator runs from 1.2V and the feedback is set so that is just oscillates reliably between 0deg C and 50degC. The slightest contact with the ball in ANY plain stops the oscillation. This cessation is detected within 3 oscillation cycles ( @3.9KHz = 0.7msec) . Deflection of the ball at cessation after 200 to-and-fro runs is around 0.008mm in horizontal, and 0.006mm in Z. It works a darn treat! The assembled probe and its bits below. The PCB - engraved on my PCB router.. The Piezo disc from the rear - with the disc holder beneath it - left. The disc with probe, fitted to the holder supported by the three points. Electronics on the rear of the disc holder The jig used to located the probe on the disc when soldering it in place. Left, main body with Z springs Right, disc and holder atop the Z springs View of the probe tip and drilled ball - also the disc holder Setting tip runout - 1/2 div @ 0.01mm div guage.
This one for the Mill, another for the lathe - a different shape to fit an arm on the ATC... Joe
Edited By Joseph Noci 1 on 23/03/2022 17:10:52 |
Jeff Dayman | 23/03/2022 17:40:38 |
2356 forum posts 47 photos | Great work on those probes Joseph! well done. Years ago I worked for a smoke alarm firm and had a lot to do with piezo disks for making noise. Never thought to use them for a probe. In smoke alarms we supported the disk with a circular knife edged ring top and bottom , the knife edge was at the nodal diameter of the disk to allow max movement / max noise. The disk was captive in a circular housing which located the disk od at 3 minimal contact points and with about 0.4 mm total clearance on the od. Made millions of alarms with these per year, about 99 % worked perfectly! I recall the disks we used were from Kyocera. |
John Haine | 23/03/2022 17:42:51 |
5563 forum posts 322 photos | Joe, that's very neat! |
John Haine | 23/03/2022 17:42:53 |
5563 forum posts 322 photos | Joe, that's very neat! |
Joseph Noci 1 | 24/03/2022 16:49:58 |
1323 forum posts 1431 photos | Thanks John and Jeff. Finished off the probe as far as I want this prototype to go - It really works well. Fitted an LED so I have a visual indication if I use it on a manual mill. Connectors for these items are always an issue - I hacked in a USB-2 connector - use two pins for power and one for the open drain to ground output to Linuxcnc for probe contact. When I do the actual one for the lathe it will be permanently mounted on the cross slide and a different format. The proto in the images is great for the mills. It is REALLY sensitive less than 1gram activates it fully, and oblivious to machine vibration, etc. A crash ( it happened..) of 4mm overrun pops the Piezo disc out of the tri-point holder with no damage - refit it and recal ( runout) and all works fine again! Of course this is only valid in XY - Z would kill the piezo disc! The USB connector pcb - held in place against a rebate by the spring seen below, when the rear shaft and cap is fitted.
Business end of the USB connector A section of snap-off blade shows how sensitive the unit is. The blade weighs 1.37grams and one end sits on the eraser so the weight on the ball is maybe 0.7grams or so.
And while its powered it sits and sings quietly at 3.9Khz... Edited By Joseph Noci 1 on 24/03/2022 16:52:42 |
sam sokolik | 25/08/2022 18:08:27 |
126 forum posts | Wow - great work! I totally missed this thread. |
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