simonr Posted January 2, 2015 Share Posted January 2, 2015 I didn't look to see what the max rating was! To be honest it was more about the wiring that already goes to the table from the controller, rather than re-jigging the controller wiring. I had considered this from the outset and have a switched 5v line at the cutting head. I'll write a Z move macro for Mach3 which only turns on the laser when the Z axis is at the right height. That way, it will avoid false readings if I forget to pozition Z. Si 1 Quote Link to comment Share on other sites More sharing options...
robertspark Posted January 2, 2015 Author Share Posted January 2, 2015 Err question... What about using two straight line projection lasers on two mounts at 90 deg apart (say either side of the torch mount [so at 45 deg to the axis]) that way the crosshairs would always be alighted regardless of height once set up? Worth a try at that cost .... What about a 3.3v Zener diode and a resistor for a 3ish volt supply from the 5v you've got for the z-limit switch.... Cheap option? Rob Quote Link to comment Share on other sites More sharing options...
robertspark Posted January 2, 2015 Author Share Posted January 2, 2015 https://m.youtube.com/watch?v=y2xlKxFQ3Hc Quote Link to comment Share on other sites More sharing options...
simonr Posted January 17, 2015 Share Posted January 17, 2015 Just added the last (I hope) bit to the cad model. I made a cable support out of the excess 8mm bright bar used for the axles for mine. I wasn't sure it would be strong enough, but even with the heavy thick cable on the hypertherm - it seems fine. It's springy, but if anything that's an advantage. I used an extra shaft collar to stop it dropping through the hole. I guess this comes under the 'options' category - but I've included the mountings as they will only add pence to the overall cost. I also drew up some folding legs - which I'll make tomorrow! Si Quote Link to comment Share on other sites More sharing options...
robertspark Posted January 18, 2015 Author Share Posted January 18, 2015 I was thinking about the potential long lengths of studding that may be required if you want a 2500 x1250 table (+ carriage clearance for full sheet cut). You could weld some inserts into the end of the 50x50 tube with a nut welded on the back or maybe have a nut welded to a sizeable pin (stop flex) then drill the 50x50 rhs and insert the pins (would require oversize hole to insert pin from inside rhs and slide across to get other pin in) (Always an armchair critic somewhere .... ) Rob Quote Link to comment Share on other sites More sharing options...
simonr Posted January 26, 2015 Share Posted January 26, 2015 Top tip for anyone considering building one of these! Don't buy one of these USB Breakout boards: As they do not allow the Torch Height Control to operate! To control a Mill or Lathe, it would be great and good value - but not so hot as a plasma controller! I ended up swapping it out for a UC100 http://cncdrive.com/UC100.html plus a cheapo parallel breakout board from eBay - and the THC works fine! I used a USB Smoothstepper on my mill and although it works well, it is very sensitive to electrical noise which made it hard to keep running happily. The UC100 is so good, I might swap one in to the mill too. I'll re-use the former one on something less firey! Si Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted January 26, 2015 Share Posted January 26, 2015 Which THC did you get in the end Simon? The same as Robert? Quote Link to comment Share on other sites More sharing options...
simonr Posted January 26, 2015 Share Posted January 26, 2015 Yup, the Proma one. Having played with it a bit - it's not bad! Si 1 Quote Link to comment Share on other sites More sharing options...
robertspark Posted January 26, 2015 Author Share Posted January 26, 2015 I must admit the thing that I struggled with (besides the TB6600 drives (recommend don't buy, use leadshine drives very smooth travel) was the PIA wiring, just the slow progress and the faf of doing it and getting it neat. When I bought my smooth stepper I looked at one of the break out boards, and really liked the RJ45 connectors or at least the idea of them, just could not justify the cost, I think that there would be good money to be made with a simplified solution and not sure why the Chinese sellers have not cottoned on to this? http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=255 There is a partial 1/2 way house which is to buy one of these breakout boards: http://www.ebay.co.uk/itm/CNC-5-Axis-Interface-Breakout-Board-For-Stepper-Motor-Driver-CNC-Mill-MACH3-ON-/221556374685?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item3395c9fc9d And then buy a set of these leads and wire one end and plug in! (may need to lengthen the leads though...) http://www.ebay.co.uk/itm/230526932638 Note, I've built mine with the intention of using the same box of drives + breakout boards + small VFD to drive my mill and lathe should I ever get to converting either of them hence the wiring has gone a little overboard. Rob Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 1, 2015 Author Share Posted February 1, 2015 Si, What spacing have you used for your grate? I was about to use 3", but it looks a bit wide Thanks, Rob Quote Link to comment Share on other sites More sharing options...
simonr Posted February 1, 2015 Share Posted February 1, 2015 I'm just using lengths of angle - pointy side up. They are free to move so I've just been positioning them such that the plate is supported but the cut traverses as few of the bits of angle as possible! I did some nice cutting for work today - making 38mm square end caps in 1.5mm 316 to weld on to stainless box section. They had been quoted a 2 week lead to have them Laser Cut. We need them for Tomorrow - and I thought "I know what to do!". They have all come out within 0.1mm of the correct size (all 37.9mm side) which isn't too bad. I really didn't expect to get that good accuracy out of it! I also cut a 'holy flange' Circular flange for the end of a pipe with 12 x 6.5mm holes in a ring, out of 6mm plate. That was spot on. The holes needed chasing with a 6.5mm drill bit but they were surprisingly good. Si Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 1, 2015 Author Share Posted February 1, 2015 Glad to hear you're getting the benefits of it now, you can probably apply that 0.1mm correction within sheetcam.... but then again I think it depends on the state of your torch consumables. I've gone the flatbar route for the grate 30x3 .... 14 of them at 1400 long which is slightly larger than my table is at ~ 1360 so as to get a bit of flex in them and they are wavey (that's the plan anyway). I've had it all working with the drives but have 8 holes to drill (getting it square is a PIA, not found a way to align it quickly yet once folded away & reassembled which was the objective)), and some spacers (qty-14x4) to tack in for the grate and I should be good for a trail run with a torch. Then the whole load of electrical interference issues I suspect will come to light. (all a bit of a learning experience I guess) I've changed a few of my belt guide bearings to flanged type as the belt was slipping off (combination of maybe minor alignment issue, speed, belt twist or deflection with from the springs). Rob Quote Link to comment Share on other sites More sharing options...
simonr Posted February 1, 2015 Share Posted February 1, 2015 I've not had any electrical interference issues! This week I added an 8 pin Bulgin connector (same sort as used for lighting rigs) to the plasma and my control box with a 6m lead made out of trailer cable. It carries the torch voltage, arc ok and the trigger. I was half expecting interference / coupling between the wires - but there is none! Where each of the signals comes in to the controller, I have added a 0.1uF capacitor between the lines to remove the worst of it - but looking at them on a scope, there is very little anyway. Si Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 1, 2015 Author Share Posted February 1, 2015 I actually fired it up last night for the first time - and the PC crashed! The HF Start on the plasma was obviously inducing spikes somewhere inside. This evening I added a few clip-on ferrite chokes on the USB, power & Torch trigger wires plus a 0.1uF decoupling capacitor across the torch trigger wires - and it worked just fine! Another top-tip is to use screened cable between the PC & the plasma cutter. The screening (earthed to the breakout board 0v line) screens out most of the interference that might otherwise be induced in the wire. I have no idea what settings to use - torch height above the metal, current, speed at which the torch moves, air pressure etc. I see a fair bit of trial & error before I get it right. Si Ahh, I thought you'd added some ferrite cores. yes, the trigger wires are the ones that concern me as the are obviously paralleled within the torch lead and then run all the way back to the BOB relay, in unshielded cable etc. Thanks Rob Quote Link to comment Share on other sites More sharing options...
simonr Posted February 2, 2015 Share Posted February 2, 2015 Originally I had ferrites all over the place plus screened cable. In it's current incarnation with everything going down un-twisted, un-shielded trailer cable, there is one clip on ferrite on the cable itself - but nothing else. Works fine without the ferrite - but it cant hurt. At least in my case - interference just isn't an issue. I was most worried about running the high voltage inc the HF Start in to the controller cab - but even that doesn't seem to worry it! Si Quote Link to comment Share on other sites More sharing options...
zim Posted February 3, 2015 Share Posted February 3, 2015 I'm just using lengths of angle - pointy side up. They are free to move so I've just been positioning them such that the plate is supported but the cut traverses as few of the bits of angle as possible! I did some nice cutting for work today - making 38mm square end caps in 1.5mm 316 to weld on to stainless box section. They had been quoted a 2 week lead to have them Laser Cut. We need them for Tomorrow - and I thought "I know what to do!". They have all come out within 0.1mm of the correct size (all 37.9mm side) which isn't too bad. I really didn't expect to get that good accuracy out of it! I also cut a 'holy flange' Circular flange for the end of a pipe with 12 x 6.5mm holes in a ring, out of 6mm plate. That was spot on. The holes needed chasing with a 6.5mm drill bit but they were surprisingly good. Si Si, Sounds like your machine is working well Could you post some pictures of items cut. On another note, what are peoples' suggestions for a plasma cutter ? I am limited to single phase. Gordon Quote Link to comment Share on other sites More sharing options...
simonr Posted February 3, 2015 Share Posted February 3, 2015 If you can afford it, a used Hypertherm seems to be as good as they get. Lots of them will run on single phase. Failing that, get one with 'pilot arc' and 'HF Start'. 30 to 40A is OK for most of the kind of stuff we are likely to cut. I'll see if I can take the odd photo. Unfortunately everything I've cut so far is now welded to something else! Si Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 3, 2015 Author Share Posted February 3, 2015 +1 for hypertherm, I have a 30, bit small really (now a 35), it will do 6mm but it would be nice to do more and get a better cut in ali. 45 is the next size up, which is better (I think it does 9mm) surprised how small it is + light weight compared to my machine (transformer to IGBT technology). I'd like a 65, but getting a single phase one I think is difficult in Europe, seems they sell two one for the US market and another for the RoW.... if I get the opportunity to go to the US, I know I'll be picking up a 65 ... just where to put in on the plane is the next question.... haha. There are other similar brands, (and maybe I'm brand biased, but mine has really impressed me, but I've never used another on, also hypertherm only make plasma cutters, it's all the do and have ever done so [and I may be wrong here] but they seem to be brand leaders in the sector because of the R&D side, you just need to read some of the Jim Colt posts. I see R-Tech do them (bought the odd consumable in the past) and are now offering 12months free interest on drip, which could be very inviting to spread the cost (never used one of theirs but I'd defiantly consider them if I had the urge for another Tig / plasma with IGBT technology for a smaller package + easy to move / relocate about). edit: this one looks interesting to me, I'd see if I could find one local to review first though. Rob Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted February 3, 2015 Share Posted February 3, 2015 ....... edit: this one looks interesting to me, I'd see if I could find one local to review first though. Rob I have that one, now I just need to get my finger out and make my cnc table for it Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 3, 2015 Author Share Posted February 3, 2015 Barry, how do you find it? I presume it is actually HF start and not touch / scratch start... I like my hypertherm, but I really would like a bit more cutting ability especially as it opens up ali + storage boxes etc, etc for the landy ... and maybe a dash etc. Just cant seem to get a clean cut with ali on mine but I am using it hand held, hence hoping for a bit of a better quality cut with the table given it's machine speed controlled + height controlled. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted February 4, 2015 Share Posted February 4, 2015 I don't really have a great deal to compare it to, however if you would like me to try a few hand held straight cuts on different materials and thicknesses I could take pictures of the cut quality for you? EDIT: Forgot to say, it is a proper HF start with pilot arc so you never have to touch it to the work piece. You can just hold the torch in the air and pull the trigger and get a 'flame'. Quote Link to comment Share on other sites More sharing options...
zim Posted February 4, 2015 Share Posted February 4, 2015 Thanks for the info. The hypertherm's look nice, but not cheap. As much as i'd love one the above R-tech is probably £800 cheaper for a similarly spec'd machine. This will be a home project machine, not needed for work jobs etc. I'll keep my eye out on ebay to see what comes available. G Quote Link to comment Share on other sites More sharing options...
simonr Posted February 4, 2015 Share Posted February 4, 2015 I was on the brink of buying the RTech machine - then the Hypertherm 600 (40A) came up for less money & I bought that! It was made for CNC so had a machine torch and a connector for torch volts, trigger and arc OK - which made it kind of easy to wire up. Si Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 4, 2015 Author Share Posted February 4, 2015 .... think the price of second hand / flee bay plasma cutters has taken a spike of late ... Barry, some photos of the cuts would be great, I'm sure some of others of the group buy will be interested. Rob Quote Link to comment Share on other sites More sharing options...
robertspark Posted February 17, 2015 Author Share Posted February 17, 2015 Some updated pictures of my plasma if anyones interested see if I can get a cut out of it next. I'm finally happy with it as it stands could have done a few things differently (like bought Si's kit.... ) , but it does all fold up quickly and neatly and is quick to assemble. The slats were 30mm / 3mm flatbar, the bit of box section welded on the end was because they needed a spacer but it works very well and they lock in well plus are not permanently deformed in any way. The slats are about 50mm longer than the bed hence the curve which is what some of the other plasma tables do, so when you do a cut it's less likely for the plasma to cut along a support / slat when doing a straight cut which then sometimes does not go all the way through (that's the theory) Few pictures of an LS7 in the background if anyone's interested / curious too. Sorry I'm reluctant to post pictures off my phone as they are geotagged (gps location data stored in the photo), hence not keen to use it (didn't sleep a wink last time I posted some pictures online from my phone). Never mind all the stuff in the background, time for a cleanup once it's done and running, and I can crack on with the transfer case again. http://s947.photobucket.com/user/rclandrover/library/Plasma%20-%2016-02-15?sort=3&page=1 Quote Link to comment Share on other sites More sharing options...
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