Machsupport Forum
General CNC Chat => Show"N"Tell ( Your Machines) => Topic started by: lucan07 on March 22, 2016, 05:03:33 PM
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Been busy of late and the conversion of the Seig X1LP super has been succesfull to date, now time to build something from scratch. Started badly as I couldn't resist a bargain and came across a couple of sets of Rails Bearings and screws at the right price Sub £300 delivered. So my starting point now is:
4@ SBR20-300mm Linear guide
4@ SBR20-600mm Linear guide
4@ SBR20-1000mm Linear guide
24@ SBR20UU Linear blocks
2@ SFU / RM 1605-350mm- C7 ballscrew with end machined
2@ SFU / RM 1605-650mm - C7 ballscrew with end machined
2 SFU / RM 1605-1050mm- C7 ballscrew
2@ with end machined
6@ BK12 support for ballscrew
6@ BF12 support for ballscrew
6@ Couplings
Major considerations, I have a workshop in a spare room in my first floor flat so everything gets carried up and down as required, and I try to limit noise to be considerate to neighbours. Been looking at Fusion 360 which I find simple and straightforward to use with the Seig conversion so knocked up a quick mock up of a machine to get some comments and advice sure there are lots of traps I have fallen in to pictures below .
My requirements call for a 700x400mm work area and max 100 mmZ axis. Not included in pictures are 2 SFU / RM 1605-1050mm- C7 ballscrews driving Y axis, either 1 or 2 SFU / RM 1605-650mm - C7 ballscrew driving X axis and single SFU / RM 1605-350mm- C7 ballscrew driving Z axis with a Chinese 2.2 water cooled and VFD. A lot of my strength I am relying on a solid base I intend to bolt whole thing solidly down onto a welded steel framed table with a solid cast iron top.
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Material wise two bed sides are100x100x10mm T section which can be backed up by another 25-35mm plate without losing work area, X and Z main components 25mm and 30mm Ecocast, first draught so nothing much fixed apart from overall size, my idea is based on ease of build, welding in the flat is not an option, also the materials used in the design are already in stock so using them is a no brainer.
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Time to reflect and rethink design a bit of input from others so a few changes made.
Knocked up version 2 this is a draft few peices omitted till I collect stock material acquired today like side of gantry just turned original on side for now and nor bothered actually mating same to bearings more for concept than actual design, also brackets mounts for screws, motors etc missing. Hopefully overall design and more importantly rigidity improved pics below sides now 6x2x1/4" Aluminium Box, cross member on X axis now original 150x30mm Backed by 2@3x1x1/4 Angle faced to 75mm x 25.4 to fit.
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Your design looks like it would make a good machine. But a word of advice, since you are building your own: start TODAY writing an Owner's Manual, and list everything you do, as you go. The sources you used for all parts, and components, as well as the drawings you have done, with actual dimensions of each component. Trust me on this, in the future, you will be glad that you took the time to create the book to refer back to. You should include screen captured images for all software settings, so that you will have all of the information readily available to refer back to, when making any future changes or upgrades. Good luck, and have fun!
-Michael
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I design in Fusion360 using (Dimensions & Description) in (Sketch/Body & Component) naming conventions that document the project, a few comments and pictures of machining assembly steps and most of my projects can be replicated or amended by anyone. As an IT consultant building bespoke systems since the late 80's you're preaching to the converted I over document everything in a manner suitable for Idiots as they usually were!
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First chance to do any work on build today half a day off so made a start, first job decide what to do about the steel and cast iron base I intended on using, top has been ground flat and its ready to go but Base weighs in above 3Cwt and Top just over 4Cwt all to be carried upstairs.
For time being I am going to put base into my lock up and try a different base to as all work in flat is likely to be lightweight, I will be selling my flat and buying a property with a workshop so the base will either be used then with this machine I originally designed for it or with version 2.0 which I have no doubt will be built.
So alternate base? As welding out of question in flat I have gone for simplicity, two sheets of 25mm MDF to make my base, bed laminated 75mm MDF whole base sealed glued and screwed, it's solid, time will tell if its solid enough, I cannot see any problems with type of work it will do whilst in the flat.
As base was drying I decided to drill and tap side rails which are 6"x4"x1/4" Ali box I used M6 with 30mm washers to attach rails to bed, M4 to mount external supporting ribs 300mm 38x38x6mm T section, M4 again to mount 20mm supported rails quite happy with the afternoons work, rails have a little adjustment available and I intend on locking them down with either loc-tite or epoxy when final adjustments made, currently as close as I can measure having just dropped them on and pinched up they are within 0.5mm over 1000mmm on the parallel.
Couple of pics below showing latest design and progress.
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Made a start on the X axis biggest lump thats been machined on the Seig since conversion, think I upset the seig when I put the fly cutter on to true and parallel top and bottom for rails, it started spitting needlles at me with a vengance!
635x150x30mm Plate backed by two lengths of 3x1X1/4" angle which was drilled and plate drilled and tapped for M4, top and bottom trued and drilled and tapped M4 again to mount rails.
Stomache was thinking throat had been cut so stopped now to eat, just two end to machine true and parrallel and main crossmember is about ready for ends to be mounted, thinking pocket the gantry sides 1/16" to accept crossmenber for strength and ease of alignment.
Spindle and VFD just arrived got a good deal on these £146 delivered and they look ok now I'm cooking with gas.
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Have a Y and now almost an X and I have a few spare hours over the weekend to come up with working drawing for Z and start machining. Impressed with Fusion360 so far simple to use and with a little tinker of the code before running mach3 the little seig conversion goes about its business with little complaining, nice to get some decent size lumps on it to cut eventually and make some decent chips.
Ended up pocketing 4mm each side to centre the gantry raiils onto Y axis bearings. the work area I will be able to use now confirmed as minimum 780x450x100mm
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Managed to get a couple of hours in over the weekend, and made some progress with Z axis, now have three smooth free moving axis and screws mounted for Y and Z still waiting on delivery of some parts so limited to working with parts already available. Time to start thinking about motor sizes required, being a novice I was surprised by the weight accumulation with the 20-30mm 5083 plate, rails, ballscrews etc used so need to work out totals and ensure adequate power from steppers drivers etc.,
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Progress being made not been able to keep up with posts as everything has been done in snatched moments as and when the free ones occured, all wired and connected ready for a test run tomorrow work permitting. Went with 5 axis BOB, 4 x DM542 4.2a drivers, 4 x 425oz Nema 23, 2.2kw HY VFD and Spindle, linkage I used 2:1 ratio from motors to 1605 ballscrews, power supply a pair of 36v 9.7amp units I had, option to swap in a pair of 48v 10.4amp will be available soon if it will be beneficial.
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So much for a day off only ended up working till 9pm, had to plug it in a try it when I got back, spindle fine, Z axis fine, Y axis with A slaved no problem, X axis just a rumble and rock from motor, too tired to even think about it tonight can't be too serious it didn't go bang! The two working axis have proved already it has all the speed I will ever be able to use in the flat and then some if it lived in a shed the shed would have been rocking. Would have been nice to have it all work but 4 from 5 is better than a kick up the backside.
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Decision made I had seriously under estimated how hard the ballscrew material was going to be, so drilling from end between steel pulley ans shaft would have wandered so.
Significant flat ground on one side and loc-tite to ensure grub screws stay put will be my plan of attack for now, just dremelled first one and grub screw replaced by an allan head A2 stainless machine screw should be sufficient to prevent rotation and lock pulley in both directions.
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Got ten minutes to inspect the plug on X axis and it had a problem caused by old age and drugs, I got older massive doses of steroids prescribed eyesight went to crap, some plonker managed to rotate pins by 90% when soldering late the other night, easily fixed glad I didn't use a 6560 for this build the driver would have gone pop and I would be soldering a new TB6560AHQ IC into the board and tales of magic smoke would be told.
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Bit of progress made over the weekend sorry to say weather was nice so my bikes took most of my free time been neglecting them too much lately they need riding and I need the exercise getting old, London Surrey 100 end of July and Box and Neath hills are both killers if you are out of shape and practice. However fixed problem of slipping pulleys before it occured, a bit of testing/tuning first cuts a few slats of 25mm mdf which I have decided to use for first sacrificial bed, had a selection of 2020 off cuts laying around from printer builds etc so using these for clamping t-slots gives me 5mm to skim as needed. Using 6mm Router bit 1st DOC 3mm 2nd 6mm 3rd 12mm MDF using 12000rpm and 1500mm pm feed no problems with cuts. I have used a BOB I was given I think its a cheap chinese import and I appear to be having occasional problems, axis will refuse to operate in one direction, jogging a different axis then frees the original axis to move as required so another BOB on its way, double checking wiring next on to do list, all wiring is CY shielded cable currently all mounted in small pc tower case whilst waiting for cabinet to arrive so may just be everything to close for comfort. VFD is mounted well away from everthing else.
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Nice work sir. Let's hope that changing the BoB cures the axis one way problem (issues such as this can occur when using an opto-isolated BoB feeding into an opto-isolated driver).
Tweakie.
( You must have some stamina - the Zig-Zag got the better of me some years back and I don't consider myself old yet :D )
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Your only as old as the woman you feel I need to find a younger one, I am only 57 this time but stubborn enough to get round and raise a bit more cash for McMillan.
Thanks for the info and yes I have opto isolated Bob and Drivers so fingers crossed.
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Nice work sir. Let's hope that changing the BoB cures the axis one way problem (issues such as this can occur when using an opto-isolated BoB feeding into an opto-isolated driver).
Tweakie.
The new Bob solved the problem thanks for the heads up, I still can't get my head around how opto isolation on two seperate circuits has can affect each other, do you have any more information on why this would cause a problem?
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I am pleased that you have found the problem.
I have not looked into the reasons behind opto - opto problems, perhaps it's timing related, it is just that this issue has been reported on the forum many times in the past.
Tweakie.
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And award for plonker of the week goes to ME!! rushed back so I could skim the bed before it got too late, I had trammed it in on an old offcut of ply last night. Set it up to face at 1.5mm DOC at 1.5mpm 6000rpm and it glided around leaving a nice clean finish, straight edge and a CREE to check and a blind man would have been glad to see it. :o Who decides wants to play some more and take just 0.2 to see how it goes, fired up the spindle and thought I would try the new hand control thats sat here for a week, DAMN straight down and 1mm ding in the freshly skimmed bed, well it can stay as it is for now until I feck it up again!!! Anyway have to remove the grease nipple on bottom bearing to skim it as it holds just off the edge since I fitted that side.
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Regarding the ballscrew hardness. The way that I dealt with my machine (actually an acme lead screw, instead of ballscrew), was to place the lead screw into the 3 jaw chuck on my lathe. Then locked the headstock, to prevent rotation, and used a cut off tool, to scrape a slot in the end of the lead screw. The slot was cut to match key stock which matched an existing slot on the motor coupling (in my case). It could have just as easily been a drive pulley slot (as in your case). The key slot cut into the lead screw was not cut all the way to the end of the lead screw. Which provided a "tub" slot for the key stock to be seated into. Once the motor coupling was assembled onto the lead screw, a transfer punch was used, to mark the center of the grub screw hole into the key stock. Then it was disassembled, and the key stock was drilled at the screw's center, to provide a Secure Grip of the grub screw of the motor coupling, into the detent drilled into the key stock. The key stock being seated into the "tub" slot of the lead screw prevents ANY slippage from occurring end to end! Tip: if you don't have a carbide cut-off tool for cutting the ballscrew, try mounting a Dremel tool with an abrasive wheel into the tool holder of your lathe, and cut the slot with that! It works, no matter how hard the steel is!
Good luck on your build. Looks like you've got it going on!