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Messages - metlcutr55

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31
my point was this, Gropper.   if a drill misses hole center by a thou or 2 or more it will follow the existing hole due to the angled edges.  an end mill bores the hole and makes it round as reasonably possible, drills do not always drill round holes.  the end mill, especially a short one will not deflect, if you lose steps you will see out of roundness in your holes.  the orientation of the out of roundness might well reveal which axis is mis-stepping.

and regarding squares, i was actually thinking about square bosses, although holes should work as well.  rapiding from one point to another far apart as possible then milling i would think would expose dropped (or gained, can that happen?) steps, i would expect the step error to occur in the rapid move which is the fastest move, and would have the quickest accel/decel, i might even do the test with the rapid in 1st the x, then in the y axis.  then maybe in both.  truthfully i have not built a single mach3 thing yet and could be totally wrong about this.

it is this potential to lose a step that can affect long running jobs, kinda makes me lean servo, tho i would appreciate anyone chiming in that has run a stepper system for long periods of time, both in hours/day and also over months and years. 

32
this would be a better test:  repeat your drilling.  then without moving the part put in a 1.25mm 2 flute end mill and bore your holes with it using basically the same program 125 times.  a drill can deflect and follow an existing hole a bit. the end mill will not.  and by measuring carefully, check the location of your 1st and last holes, see if they match the programmed dimensions.


another good test might be to mill a square, say 1" or so, on an aluminum block on the left end of the table then another on the right end of the table.  use rapid traverse to get from 1 end to the other.  repeat the program many times.  after a couple repeats, end mill spring would be eliminated, you should no longer see any shavings after that if things are repeating 100%

nice to hear good things about the geckos, i am considering them too, although i am trying to gather the courage to try a servo setup which is a little more complicated for an electronic noob like me.

.

33
i will try to attach a pic



the pic makes it look a bit large, it is mostly the cabinet in back

17" dia swing, 40" z travel, weighs about 4000 lbs.   8 hp spindle motor, i am driving it with a 20 hp rotary phase converter.

3 phase 208v to the machine, i needed a buck-boost transformer to bring it down, machine built in brazil i believe to their

electrical standards.

those fanuc red caps supposedly rapid it to 290 ipm, and i never had any stall issues in rapid or in the cut

cuts of say 1/8" plus deep per side in mild steel @ .015 ipr, plenty of torque, as it should be driving through a gearbox.

my max speed with the motor in high range about 1200 rpm, tho the gearbox will go to 3000.  this limitation

due to the mass of the 10" chuck and because my power companys transformer is on the small side, they

promised to change it, that was about 10 years ago.

my reason for avoiding used components is that i want some warranty behind them, i want a simple install, i am no troubleshooter.

i want the install to be as simple as possible, as i learn, i can upgrade later with more confidence if i find a need.

thanks
ken

.


34
hi Hood!

all i can read on the z motor is correct in my ad desc "A06B-0032-B077#7076  3.2 amps 176 volts AC" there is more there but id need to get the motor out to read it.

looked at the faulty x motor again, "0.5 kw continuous  166 volt 3.2 amps  200Hz freq.  speed- 3000 min(-1)"  it has what looks like a 1/2" dia shaft.

fwiw, these are fanuc red cap motors.

i have no interest in reusing any fanuc in the machine.  the only servos i have considered are the teco .75kw unit offered by Machmotion, by themselves without a kit they run over $800 ea for driver and motor.  too rich for me right now.  and i do not want used components.

i am still interested in that servo kit with the geckos, although they appear to be out of stock.  they appear like they back their product, and should their drivers not be up to task, once i had learned enough to set up the system in the 1st place, perhaps replacing with a stronger better driver would be an easier task for me. and i do like the use of encoders vs just having steppers.

i am not yet convinced i am up to the servo install without very basic guidance from the seller and this community.  as i said i am making pretty good sense from the stepper videos listed below that i have been viewing, and am leaning stepper, because of cost and simplicity.  i am looking with interest at a 2 axis version of this kit,

http://www.automationtechnologiesinc.com/products-page/stepper-nema34-3-axis-kits/nema-34-stepper-motors-3-4-axis-kit-1

once again for simplicities sake, the driver power supply being built in is attractive to me.  might not be the best choice, it is just a guess on my part.  i might request a fancier breakout board, to possibly control a vfd in the future.

once the fanuc is gone, except for axis control i have just spindle off-on, spindle motor hi-low range selection, spindle brake (mechanical, should trigger with the spindle off, then release once rpms are 0) to figure out how to do.  the other 2 features to control are just coolant and oiler, i can run these manually until i have time to figure it out.  oh and the limit switches, they appear to be 2 switches with ramps and rollers on ea axis, with the fanuc on, you pulled the joystick to home the axis, it rapids to the 1st roller, then slowed and hit the 2nd roller, reversed the axis for a short direction, voila you were at home.

i will have a bunch of relays and contactors left over unless someone makes me an offer for the fanuc system turnkey, but unless my electric/electronics helper encourages me to use these i will likely just source these new also.

ive had no offers on the fanuc system complete, ill wait a little longer, then start to see if anyone wants to buy as individual components across the boards, on craigslist and ebay.

what should i do next?  thanks, and keep the input coming.

ken





 

35
thanks Hood

i do understand about the acceleration of the servos, if i were drilling a 20 x 20 pattern of 400 holes on my dc brush servo mill, say small holes, in a 4" x 4" square for example, my mill would jump hole to hole very quickly, due to the acceleration even tho the rapid is only 150 ipm.  i can see watching the stepper vids that task would take noticeably longer.  if the guidance from the sellers of the servo kit is good i bet i could do it, but looking around the net, i rely on vids like i mentioned before, from Patrick Hood-Daniels, and another set i watched yesterday, cnc g704 parts 1 & 2, from someone called "n1bpd", all on youtube.  im pretty sure i can do what theyve done, but they are both stepper based and i find no step by step simple vids like those for servo setups.

regarding the gecko kit i mentioned below, i picked it because it has the biggest servo motors i could find from a vendor who seems to have large sales and a good reputation. i would not be opposed to keling, viper, dugong or whale drives, im not sure if any of these are the Hungarian drives you refer to, but i whatever kit i choose will have to have directions that are not vague to the neophyte (me).  i will need step by step instruction, on a basic level, like the videos i have mentioned.  or a lot of handholding here on the forum.  i read somewhere that 75% of the basic cnc builds never get completed.  i dont want to be part of that group.  id like a servo driven lathe, but a stepper driven lathe would be preferable to a manual lathe and a box of servo components in a box under a bench.  for me ac motors and drives are likely out at this point, just because of cost.  also that when you say tune PID, i dont even know what you mean.  likely i can learn.  im all ears fellas!!  thanks!

ken

36
i am grateful to see the quick replies to this thread.  i will respond here to all who have posted so far.  feel free to tell me if my thinking is faulty, i am just a machinist, all the electronica is new to me.

regarding stepper vs servo, i understand well that the servo is the more capable system in most ways.  the reason i find myself aimed at steppers is not so much the cost but what seems to be the simpler install.  i have been reviewing Patrick Hood-Daniel videos on youtube, his 9 part series that have "CNC Electronics" in the title seems to me to be concise, i understand what he's doing, even though my electric/electronic knowledge is weak.  if i could get guidance at that level, i like the looks of this servo kit:

http://www.automationtechnologiesinc.com/products-page/servo-nema34-kits/3-axis-nema34-1125ozin-72v20a-psu-g230x-gecko-driver

im sure they would sell me a 2 axis version, but im not sure i could install it, not being an electronics guy, and not knowing how concise their instructions would be, or how much support they could/would provide via phone or email. i am prepared to work on the install slow, and safe, just worried i will fry my investment.  a stepper kit in the 1800 oz-in range or a lil bigger looks to me to be an easier install.  but again, this is an unexperienced opinion.

regarding speed, ive watched youtube vids of a bridgeport knee being driven at 120 ipm by servos, 50 ipm by steppers, and ive seen cncmasters claim their 14 x 40 lathe max speed is 100 ipm.  i think i could live with 100 ipm.  their unit is direct drive, and they claim 40 tpi on their lead screw (seems high).  my lathe has not yet been closely measured, but the pulley reduction and ball screws look similar to my mill, which would be 2 to 1 on the pulleys and 5 tpi on the ballscrew.  i am hoping i can use this to my advantage, 150 ipm rapid is my mills max speed, (80 on the knee, just because it works smoother that way) that would work fine for me on the lathe, tho with the fanuc stuff it is closer to 300 ipm.  the 17 yr old kiwa horizontal mill i run days is just under 1800 ipm rapids, even that is slow these days.

regarding the fast trace, i ran it for about 8 or 9 years.  it was basically reliable, in that time i needed an x servo motor and the crt unit replaced.  then the keypad developed some small issues, and now the 914 error (see my post in the bargain basement) and i need the fanuc guy again.  im lucky enough to have had 2 guys local at $50 an hour, but the 1st guy passed away, and the 2nd is not always available quickly.  and the real factory fanuc guy gets much much more $$.  my move to a pc control is because i cannot afford to have (or wait for) the Fanuc man come here, as i approach (semi) retirement.  i need a system i can understand and maintain myself.  including parts and costs.  a refurb power supply exactly like my item 2 in my bargain basement post was listed on ebay a few day ago for over $2000.  yikes.  if i lose a bit of performance, i will have to live with it.

thanks to all, keep those comments coming.  whats my next small step?



37
i want to convert my lathe to mach3.  it is a 17" x 40" gear head engine lathe, has the fanuc 20t control on it.  personal computers i understand a bit, and ive been doing a lot of internet reading and video watching about mach3, im beginning to understand the basics, why a breakout board, steppers vs servos, analog vs digital, step + dir, etc.  ive watched a bunch of the Artsoft tutorials and a lot of it makes good sense to me, tho when folks start talking modbus, incorporating motion controllers, etc, it gets a bit fuzzy to me.  ive watched these folks vids, http://buildyourcnc.com/CNCElectronicsandWiring.aspx and http://buildyourcnc.com/wiring.aspx, most of it makes sense to me, tho ive never attempted this before.  ive looked hard at the Machmotion kits, could probably afford their stepper lathe kit, looks like a great effort on their part, but something in me says turn to the mach3 community, take this in little bitty steps, and i will save some $$ but more importantly i will understand what i have built with the help of others when i am done, which is very important to me.  i run a big fanuc controlled workcenter days, ive watched the fanuc man fix the machines around mine and know the $$$$ he charges, and the $$$$ the repair parts cost.  i need him to not have to come to my garage, i need to be able to fix my own stuff, and from reading the huge manuals that came with my fanuc control, know this is too much for me.

so i think ive taken the 1st 2 bitty steps.  i have listed my complete fanuc control with motors for sale in multiple places including here, goodbye, perhaps i can generate a lil $$ for my conversion.  once the fanuc is gone, i will be left with a nice solid engine lathe with a 2 speed 8 hp spindle motor, running on 208 v 3 phase, yup, not 240, bucked down off a rotary phase converter.  the 208 is i guess european and/or portugese style.  i also have a full set of electrical diagrams, also in portugese.  the motor has a mechanical brake, turn off the spindle, klunk, the chuck stops, very quickly.  there are mpgs for the x and z, a high-low hand switch for the spindle motor, coolant pump, and an oiler.  there is an incremental spindle encoder there, not on the spindle itself, but on the output drive of the gearbox.  oem (hiwin) ballscrews are in place with pulleys on them, and places to mount new axis motors.  bunches of relays and contactors in the cabinet too, i know their basic purpose, but couldnt tell you one from the other.

my original dream was an enhanced version of what i had (i really like the mach3 graphics and screens) complete with vfd, mitsubishi servos kit from Machmotion, now i am looking at a different approach.  bitty steps.  i am looking at basic stepper kits from motiontek and automation technologies inc.  perhap with a higher end breakout board to be there should i decide later its time to go servo.  or add the vfd.  am i barking up the right tree?  will they help me the non electronics guy get this running?  how about you guys?  can i get guidance here a small step at a time?  theres plenty of time, and enough money so i wont be looking for the cheapest component(s) from ebay with engrish documentation.  i want to do it right, simple as possible, fancy is not needed right now.

so ive decided the fanuc is going.  and ive decided to stay very basic, just get her running again.  i have a competent electrician/electronics guy available, but want to do as much as i can myself, so i can learn.  he will be there when needed, electrocution is not on my list.  i just want my lathe to run again, to be able to be run with the handwheels (mpgs) like a manual, and also via cnc, do basic contouring and threading, and i want to document this, so the next fellow who might be a machinist and a mechanic but not an electronics guy can benefit from my experience.  there is obviously a ton of knowledge in this community, an awful lot has been done with mach3.  my task ahead seems simple compared to that.  but i dont have that ton of knowledge.  help me out, what is my next bitty step?

thanks in advance
ken

.

38
General Mach Discussion / Re: OEM Mach3 machine suppliers
« on: November 18, 2012, 10:38:45 AM »
my mill is knee driven, has about 15" of z travel, the spindle can be used free for tapping.  it was built by cnc automation inc of amherst nh and they still make them.  it is driven by their own cnc control software not mach3.  mine worked well for 10 years, but have had issues with replacing old computer parts for the last 3 or 4 years, its running fine now with the help of a friend more legacy computer savvy than i.  im sure they use newer computers now.  never any issues driving the knee.  their control software works fine, tho i wish i could switch to mach3 myself.  but the "motion control" board in there is unlabeled, a mystery to me, and they dont provide any help with this older machine, they want me to upgrade to the newer control.  i guess i would say if you chose to deal with them, their support was great for the 1st 5-6 years, then i was invisible to them.  if you were willing to help him with just the mach3 and pc part, this might be a good start: http://www.cncmasters.com/index.php?page=cnc-supra-vertical-knee-mill.  it is however, z spindle driven not knee driven.  mine is based on the 10 x 54 acra and it has held up well for me.

39
being in a position where i want to pull a old fanuc system off my 20 yr old nardini engine lathe, and replace it with a basic stepper system, this thread has been interesting.  with the old fanuc, i could count on homing and then counting on the machine to be exactly where it was supposed to be , machine coord wise. going to steppers with no index pulse, having to rely on the quality and repeatability of the home switches, has been one of my concerns.  even my servo knee mill can err, if the switches get dirty (ie cast iron jobs) and react slowly and differently than the last time they were used. but this is usually easy to see, as the error is often a full motor revolution or a multiple of.  the lathe has never failed me in this manner, the switches are of much higher quality, and are very well shielded.  it is very handy to be able to count on ones work coords on startup, but with no index pulse on the upcoming lathe steppers, i fear being off a thou, or 3, that could be a problem, not easy to see by eye.  i had thought if i mounted way on the back of the lathe, one of these (http://www.edgetechnologyproducts.com/pro-touch-off-gage.html) for the x and one for the z, kept them covered, and mounted a ball on a stem on the cross slide, the x & z machine coords could be easily checked by hand at any time.  perhaps a nicely made sq and // block could be subbed for the gages, then using a pc of .001 shim as a feeler to do the same thing.  checking the mill is easier, pick up a known work coord, or mount a permanent reference on the table somewhere as someone here prev mentioned.  the lathe is a lil harder, but this might work?  your thoughts? and thanks.

40
General Mach Discussion / Re: Cutting Fluid for Aluminum
« on: September 26, 2012, 06:44:21 AM »
i have used crisco shortening.  it is paste and stays where you put it.  but if you dont clean it up, it is organic and can decay creating a slightly rotten odor. i have also used wd40, crc and the like, work good.  i finally settled on walmarts tech lube, a wd40 generic, very cheap, doesnt lubricate anywhere near as well as the wd but used solely as a cutting fluid is fine.  i have heard others say for a nice finish on alum make the final pass using a squirt bottle of isopropyl alcohol, just heresay, i have not tried it.

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