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  • charliex 11:32 pm on January 27, 2016 Permalink | Reply  

    Pulleys, motor mount and head spacer 

    These auto youtube/google videos crack me up, it is probably the music .

    We decided to add a head spacer of 64mm to the head, that way the motor would have a better amount of clearance. I found a piece of stock 6061 that was 4x6x3" so close enough, modeled up the mounts in fusion360 simple head spacer. I had to run out yet again to lowes to grab M10 and M12 bolts, 100mm graded. Everything I think I have all the bolts, we need more. Usually the big box stores have a poor stock and they always sell in ones and twos, which is annoying especially since the barcode on the plastic bag wears out fast and checkout ends up being longer than finding them, plus the cashier and people behind you probably hate you. with all the little tiny bags of one bolt, one washer , split, nut of each size, and the pencil thing they give you to write on a plastic bag…

    this thing keeps growing, not sure how much load it can carry

    mmca is making the new pulleys on the HF mini lathe, i like this pulley calculator because it shows rpm and you can slide things around, we’re using a 4" 1/4" large 2" 1/4" small , approx 4" 3/8" center , RPM large is 3600

    he was working on the lathe with a non chip cutting lathe bit, so it’ll often spiral out the cut and attack the operator, i was trying to catch an example on video. this is a test pulley we’re cutting to test out the process. we ended up with a bunch of these swarf aluminium tumbleweeds.

    Belt Length 19~3/16"
    Ratio 1 : 1.89
    RPM Small 6800 Large 3600
    Belt (Surface) Speed 4005.5 ft / min
    Pulley Gap 1~3/32"

    Using Gates 3M/5M v belts, 3M487 which is 487 mm /19.2" long

    Making the top surface nice and flat, and with a HF mini lathe , that is some fun.

    Cutting the pulley out.

    here’s the finished pulley.

    we wanted a straight hole into the pulley for an allen screw into the keyway on the motor shaft.

    I used a V bottomed tap guide and a centre punch to make a pilot mark for the drill press.

    To make sure i had a straight hole. I used a digital angle gauge with a magnet bass, attached it to the top surface of the tap guide, then put the tap guide onto the drill bit while mounted into the drill press, then zeroing out the gauge. next mounted the the pulley+vice to the drill, put the tap guide + angle gauge onto the top and rotated it til it was back to zero. This way the hole was being drilled from the reference of the drill itself , not the table etc.

    and it worked, probably overkill but circles are hard.

    also grabbed a 4x x 4 1/2" by 1 1/2" 6061 block to mill into another pulley..

    for the head spacer, the 4x3x6" block needed cut down a little, so slap it on the horizontal bandsaw.

    a long time later

    note to self(others) set the tension first and make sure when you think, hey isn’t it taking a really long time to cut that the top isn’t sitting on top of the block. this block is 4×6" which is the size of the cutting area, but you can’t cut this size horizontally longer, has to stand up like this. I would have cut it on the bandsaw which i put a much better blade on, but we wanted the little machine to make it all the way though, unfortunately at the very end the block loosened and cut off a tad more at the bottom than we wanted.

    This made the facing operation an overall 0.013" cut instead, which ended up working out really well in the end.

    This step is making the soft jaws parallel with each other and more importantly the machine ,the idea being that this surface will be as parallel to the cutting surface as is possible with the current setup, then we’ll put the head spacer on it and face it, flip it and do a face pass on the other side. targeting a depth of about 2.5"

    We replaced the vice jaws with soft jaws and cut a grove in each side using an offcut 1" block of tool plate as the side references.

    facing the upper head spacer. cutting off about 0.002" each pass.

    after the facing operation, on to the fly cutter. we were 0.1" off on the width which was a damn shame, since it meant having to move the y 0.3" then pass back and forth. This is a single point cutting tool from the lathe that makes a very nice surface finish. this isn’t for looks, we need this block to be as parallel to the front/back as possible. Any deviance will show up later when its installed on the mill and it’ll affect out our ability to cut.

    before the fly cutter is run you can see the surface finish is pretty good and there is that low spot i mentioned earlier after the horizontal bandsaw it is a small defect and won’t affect the overall stability of the block, we’d rather have the girth since more Y axis movement.

    here is the finish after the fly cutter operation, again .002" cut, about a dozen passes

    mmca pointed out at this level you can see the variations in the ballscrew since it isn’t perfectly made so for each turn it won’t move exactly the same amount. the interference patters are neat

    that was it so far, next is to cut one hole in the middle, counter sink it to fit onto the machine and drill 3 holes for the M10 bolts. this is the bolt pattern we’re following.

    after measuring the corners and middle it came out to 2.54" within the tolerance of the calipers, so pretty good.

    here’s the VFD

    you can make a 10 5×2 idc ribbon cable to extend the control box.
    the power cable, i used a dryer cable as its called here at lowes, its a NEMA 13-30P which can do single phase 220V + 125V since washer/dryers often use both. We will just be using the two 220V hots + earth/ground, no neutral. Totally overkill but the idea was to have an outlet for a welder, which didn’t work out since the sparks installed the wrong cable, but plenty for the vfd+motor and the breakers are set to the wire size.

    these are the stocks for the side mounts, ready to mill.

    that was about as far as we got for this day. my line laser arrived as well, this is for a scanner project.

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  • charliex 11:30 pm on January 27, 2016 Permalink | Reply  

    adding the new motor 

    I picked up a 1HP 56C ironhorse from automation direct motor and a 2HP VFD , the 1.5HP was out of stock, and i accidentally ordered the 2HP motor but changed it before they shipped, I should have kept it, but i’d rather swap out the general purpose motor to a inverter duty motor later.

    The difference being the constant torque ratio being 20:1 vs 2:1 so a general purpose motor won’t give anywhere close to the torque of an inverter duty motor at lower speeds. general vs inverter

    These pop up on ebay often so i’m looking out for the killer deal . The inverter duty is generally 3-4x the cost.

    I designed a really nice motor plate in fusion 360, made it all fit the motor and then was told, thats no good since heat.. tsk tsk. well it taught me more of fusion360 so thats good, so i replaced the nice design with 5 holes and 4 slots…

    Then milled it out on the C-Beam plate maker ( this is what this machine was designed to do )

    Here it is mounted to the motor (the left side i’ll cut off later) those are 3/8" 16 1"inch socket cap bolts.

    the old motor looks like this, its tiny in comparison and works out to about .2HP

    A360 for the 56C motor plate http://a360.co/1m4pLhK

    the cool one looked like this, bad for heat though

    i used this motor in my modelling https://grabcad.com/library/stainless-tenv-motor-56c-1 its a different motor but the base is right.

    The we face milled a couple of long pieces, these will go along the side of the head and the motor plate will bolt on to it.

    Likely will use a 2.2inch and a 1.2 inch pulley to give a 1.86 ratio. this all i had time for this Sunday night. more next week.

     
  • charliex 11:30 pm on January 27, 2016 Permalink | Reply  

    gonna need a bigger motor 

    This is the have at it and see what happens.

    and that is what happens with a 0.2HP motor and possibly uncoated endmills.

    so now we’re looking into a VFD+56C frame motor around 1HP and 29 lbs of weight to put on the head. Once you add a lot more weight to the head you’ll need a counterbalance, springs etc to help it lift back up.

    the part was made to test out 2.5D/3D milling where the Z is moving up and down during a cut as well as the X/Y, turned out decent when we altered the cutting depth so it wouldn’t bog the motor down.

    motor 1 HP

    VFD

    Interestingly A.D. say that this VFD isn’t the best choice to drive a mill because of the low speed settings it’ll drop power significantly, but a lot of people use them.

    Also have to decide on a base RPM 1800/3600 with the pulley ratio (1.56)

    The part eventually came out decent. I just made a bunch of shapes in Fusion360 and went with it.

     
  • charliex 11:29 pm on January 27, 2016 Permalink | Reply  

    OpenCV3 + webcam/camera 

    Started playing around with OpenCV3 to see how well i could get it to measure holes and distances from a webcam (using a calibration object or telling it the distance) spent a few hours on Sunday with it and this is how far i got with it. HoughCircles + various filters, it’ll detect tri/rect/circle/squares

    The object is the top of the Z axis column.

     
  • charliex 11:29 pm on January 27, 2016 Permalink | Reply  

    Installing the Z axis. 

    Finally started the Z install.

    Removed the flashcut motor mount, and the removed the two retaining nuts at the top, one jam. they come off easily.

    the collet tool i use on my CBeam machine fits perfectly.

    Undo the head bolts, but don’t remove them yet and rotate the head. I put a block of wood under the motor to hold it

    the two bolts in the middle there are what connect to the Z axis platform and the lead screw. remove these, loosen the head bolts and the lead screw will just pop out . the mount to the head is a two piece part. so it comes away easily.

    Removed the manual jog wheel, just a few bolts on the side and it pops out.

    the old lead screw and z axis connector, the circular part fits in the front block which bolts to the z axis gantry. it can move backwards and forwards and fits inside a key way. knowing this earlier would have been useful

    the hole left behind

    so here’s the first indication we’re going to run into issues later, look at the hole patter its not even close to what it ought to be the top z plate has a lot of clearance and it can move around a lot, the M8 bolts slop around. note the bottom left hole is so far off its actually visibly cutting through the casting in the hole. . I used an internet attained internet PDF for those hole positions, welp (and pardon the irony) information off the internet isn’t always accurate

    bolts removed

    remove the head , the three outer bolts sit inside a channel, one can fall out into the column , not hard to get it out but take care here. lift the head away then slide the z plate up and off.

    to put the ballscrew and the ballnut to z axis plate mount in there, we dropped the nut into the machined mount and held it there while adding the four bolts, its fiddly but you can’t really install it whiles its mounted to the ballnut


    later one we’ll discover this forward distance is quite important and the mounting bolts in the top plate being off will cause it to bind at the top, so we ended up superglueing a couple of small belleville washers to the front of this to give a small spacer of about 2.7mm, since we can then change the gap with the pressure on the bellevilles it means we can test it later and let the machine pick where it wants to be, before bolting it all down.

    top plate mounted (with only one M8 bolt), than ran it up and down a few times to let the ballscrew settle into place with no binding.

    and here’s a test of it unloaded, moving at 100 IPM , which is the limit i set in the controller

    we didn’t have a pulley for the ballscrew z, and the old one had center hole too large so onto the lathe to make a brass insert with two holes for the allens to go through. didn’t get photos of that operation though.

    ended up ordering some off ebay, that had flanges and about the same build quality as our drill press version.

    back together and leveling out the table, manged to install it with .0001" off! but of course when we tightened the bolts down it moved as expected, so tram with a mallet time..

    testing the backlash, tested out to .009" on the first go, which is when we had to go back , find the binding, realise the mount holes were so far off , mark them out and then remount it all with only one bolt, so have to recad that Z plate mount and plate again. So for each mount i’d check the machine first, or use slots in the mount. we didn’t preload the double nuts with bellevilles on the Z so the backlash is higher than we’d like, but still much better than it was. Having the max speed go from 15IPM to 100IPM is worth it.

    i have the china/ebay quick tool changer things in ER20A with collets that were about 1.99$ each !

    Super!

    Super Precision 14 PCS 1/16"-1/2" ER20 ER-20 Collects Set With 1/8 1/4 3/8

    New 10pcs C3/4 ER20A 1.38" Collet Chuck Straight Collet Chuck CNC Milling Lathe

    the holders are decent, the collets are OK but since they cost just about the worth of the metal, i’ll upgrade them as we go along.

    also picked up this one way bearing on a pillow block, its used for mounting the tools into the r20 holders when its off the machine, insert and tighten, then flip to the other side to loosen. tormach sell them but they’re probably available elsewhere. the ebay pulley is in the background too, we’re doing 2:1

    the holders and collets arrived in a few days.

    unfortunately i had to run off to ER as we were about to cut since my gpa was admitted again (he’s ok). but mmca managed to cad up a 2.5/3d cut cone to test the new Z axis.

     
  • charliex 11:28 pm on January 27, 2016 Permalink | Reply  

    Z mount 

    Made the top plate of the Z axis mount, and face milled off the rest of the Z mount.

    Don’t CNC during halloween, here is mr pika running a facing operation.

    i was running the fog machine outside, the garage filled up.

    I bandsawed the outside of the top plate, using a piece of metal as a guide, that metal wasn’t straight so i miscut the left side.. on otherwise a nice part, we did break one drill bit because the stock was slightly deeper and disagreed about readjusting the Z 0.0 adding on the difference etc, instead of just redoing the CAM, the answer was of course redo the CAM since the retracting was a fast partial retract so it clipped the edge of the hole and snapped. You can see it on the inner circle of holes middle left,. shame since the part had a mirror finish on the mating side after a face mill. but its all luckily cosmetic and the idea here is to build parts that are better than the existing ones, then redo it all again. There are three 31mm bearings inside the centre hole.

    it’d mounted nicely to the ballscrew with an interference fit after very slightly knocking it down with some 1000 grit.

    We’re ready to mount the part now and see if it all fits. here’s the A360 of the latest model http://a360.co/1GdnYAf this is the Z plate and mount. We need stronger belleville washers, so didn’t get to fit it up, should be next week.

    After that we may move on to a motor update or extend the Y axis, the current motor is only good for about 0.2HP/149N/m.s which is pitiful. Looking at a 220VFD with a 56C frame motor.

    The Y axis is longer ballscrew, put the stepper on the back of the machine, add a two inch block between the table and column, and a 2" , 5" diameter round stock on the head.

    been buying these bearings

    http://www.aliexpress.com/item/7002C-P5-Spindle-Angular-Contact-Ball-Bearings-ABEC-5-7002-7002C-7002AC-15x32x9-SUPER-PRECISION-BEARING/884362507.html

    http://www.aliexpress.com/item/10mm-Spindle-Angular-Contact-Ball-Bearings-7200C-P5-SUPER-PRECISION-BEARING-ABEC-5-7200-7200C-7200AC/1308423884.html

     
  • charliex 11:28 pm on January 27, 2016 Permalink | Reply  

    video of z plate cutting 

    there is a strange cadre of people out there ( i’m one of them ) who’ll sit and watch a video of a machine cutting something, even something this simple

     
  • charliex 11:27 pm on January 27, 2016 Permalink | Reply  

    compressor notes 

    So since i added the 30 gallon noisy-ish compressor a few days ago, i thought to myself i’ll just install it next to the CNC for the moment since that is the noisy/messy corner. When installing it , i put it on the same circuit as the CNC’s motor while thinking, i should remember to move this since if they both run at the same time they’ll pop the 20A fuse..

    So of course next day, we start running up the mill, i’m CAD’ing, mmca and mr pika are working the CNC. I go in the house and to grab something and i hear a lot of air, sure enough the fuse has blow, cnc is down, pc is down, compressor is full of air, my pc is also down. . aha right that 20A circuit, after resetting the breaker and moving the compressor to a different circuit, and making a mental note to add UPS’s all over and separate all the PCs ( and cable modem/routers) to a different circuit. We were off again.

    So we’re cutting away and of course this machine is a new build, so its prone to things going wrong and we’re usually watching it while it cuts. Since until now we’ve been using canned air as we are ecologically friendly, imagine when a fairly large compressor kicks on about a half a metre away from you, heart attack time which isn’t good since both my grandpa (wife’s side) and my brother (my side) are in hospital for quad bypasses and other heart issues.

    So I figure after the part is done, i’ll relocate the compressor out side for it.

    I had some old wood lying around from shelves that were in the garage before we moved in. So i built a hobo shed for the compressor, ran some 300 psi tubing for it and mounted it. I’ll change it out to black pipe when I’ve got it settled as to where it will all go.

    Hobo shed, sawzall, scrap wood and some screws.Even though I’ve got some nice wood working tools I used all the crappy ones. 5 minutes later. I’m sure the neighbours regret buying that rooster last week.

    mounted the dirt filter/moisture trap inside the garage with a quick connect.

    great, that’ll work for now and hopefully no more WTF what was that when we’re doing delicate machining etc. I should know better since when i first started air brushing i used a noisy compressor, and while i was painting it’d clatter to a start usually making me jump and paint stuff that wasn’t meant to be so, learnt that lesson and bought a supersilent 20A for that many years ago.

    Compressors are usually fine outside even in the heat, the motor and compressed air is a lot higher temperature than most ambient temps anyway. I left gaps in the front and back for airflow and i’m not permanently running it, just when i need it. que horror stories from some , and others with the I’ve had my compressor under my bed for 100 years with the wife , four cats and a subway franchise and its always been fine. It is oil based too.

     
  • charliex 11:26 pm on January 27, 2016 Permalink | Reply  

    Z column top adapter. 

    Milled out the top part of the Z column this plate goes on the top and holes the bearings for the Z ball screw.

    Created and CAM’d it in Fusion360. http://a360.co/1GdnYAf Design is there, though be warned haven’t test fitted it yet. Took about an hour to cut out of 7075-T6 aluminium with two drill bits 1/4" and 1/2" end mills. Bought the bearings from alibaba they were nicer than local sourced , claimed ABEC5 rated. The last ones we got had laser marks showing the high spots, but who knows.

    We’re using two bearings at the top + a spacer, the spacer is the outer race of another bearing, yep we use bearing races instead of precsion washers/shims.

    Came out decent.

    Getting close to adding some sort of collection tray/enclosure.

    Also finally picked up a compressor so no more canned air , added an electronic solenoid + SSR to allow it to be controlled from the master control box. Used this solenoid control which is 110V.

    control valve

    cad’d up the top plate that holds the bearings too, that is in the file linked above in A360. Next steps are to cut that out, run a boring bar over the bearing hole in this adapter and i guess we’ll try to fit it.

     
  • charliex 11:26 pm on January 27, 2016 Permalink | Reply  

    Cutting out the Z ballscrew holder. 

    Started on the Z ballscrew holder.

    So we started cutting full depth with 0.375" end mill and it looked like it was going well, there were some odd looking rapids and sure enough the Y axis was slipping. After a few tries and dropping the speed and DOC it was still dropping, so we looked at the machine setup and for some reason the rapids had been changed from 2 in/m^2 to 200 and 500 for cornering, which is impossible on any machine so its odd you can set that. So once that was fixed it went off to cut, Unfortunately the gopro battery died after all the messing about and it missed the aggressive spiral helix and circle cut.

    once we put it on for first fit, it didn’t quite slide the whole way, forgot to break the edges. So after that it went on perfectly. this is really the first part we’ve done as a fully CNC part, no bandsaw or drill press ( though we do have to add two holes on the back eventually)

    now i’m finishing up the Z plate and we’ll cut that next.

     
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