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#62
Thu 04 October 2012, 00:00
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Be careful with those, if using a wire larger than 0.75 sq mm things get tight inside.
In my case the thread on the male ripped the heat shrink just a little bit, enough to get a contact to the ground. Drive tripped and acted like dead, silly me I plugged it in another one... Luckily it only killed 2 mosfets on each and a resistor so I fixed it quickly. 
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#63
Thu 04 October 2012, 11:14
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This is what I used:
http://www.radioshack.com/product/in...tent=CT2032231 http://www.radioshack.com/product/in...tent=CT2032231
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#64
Sun 07 October 2012, 06:08
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Most have just started direct wiring the motors. It reduces costs and removes fail points.
I even suggest only using compression type fittins at the control box to pass your wire through. Either straight to the Geckos or to a terminal block. If you go from the motors to the Geckos you can eliminate up to 6 points of failure per wire. 24 per motor or 96 for all motors. Where I get 96 fail points? Each side of the plug at the motor. Each side of the plug if you have terminations at the control box. Each side of the terminal block. So that is 6 points on one wire x 4 wires x 4 motors. Oh yeah - the plugs and terminal blocks could fail also. Not so much the terminal blocks. So add another 48 fail points bringing the total to 144 possible points to fail. I think I am doing my math correct on this. Someone check me though. It is early and I am waiting on my coffee to brew  Wow I had never actually sat down and counted that before !!!
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#65
Sun 07 October 2012, 07:47
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LOL!!! Getting rid of the connectors is the best decision I'd made when I built my 1st MM. confirmed by my current Plasma table built which I decided to make use of the pile of connectors left-over from the router built
 As for the plasma table, I'm now regretting using connectors... there are just too many possible error points... Mike, you forgot to include the E-stop, remote buttons & proximity switches...
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#67
Mon 08 October 2012, 04:16
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John,
Those look like your standard Trailer 4 wire connectors. Great idea!
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#68
Mon 08 October 2012, 04:22
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Those look like hard drive dvd etc connectors for power, 12v gnd gnd and 5V
its molex 8981 connector
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#69
Tue 30 October 2012, 22:01
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So, in getting ready to wire up my control panel, it occurs to me that the
Last edited by Zouave; Tue 30 October 2012 at 22:31..
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#70
Tue 30 October 2012, 22:29
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Lets get the terminology right. "the flat 25 conductor printer cable" has a common name "Ribbon Cable".
There are no simple answer to your question, no one know when & where the Evil Interference Noise will strike... until you get into trouble with it... All you can do is try your best to stay away... Some of the good practice in laying any wires I know & practice are 1) give some air between signal cable from Power cable 2) give ~25~50mm (1~2in) from any inductive components, eg transformers, motor, solenoid, electromagnet... 3) try not to run wire alongside, if you must, try to space them out, if you can't, cross you fingers & pray nothing bad happens. 4) if you must cross wires, make sure they cross perpendicular to each other. 5)lay the ribbon flat on grounded chassis wall/plate & minimize as much length flying across air. The logic is :- when the cable is in the air, it will receive all sort of noise/interference from every direction; When the cable is laid flat on the grounded chassis wall it will reduce 50% chance of noise/interference. So far, I have little problem with this kind of layout arrangement so far but if you have any problem, you can shield it by sandwiching the cable between the Chassis & a Aluminum foil/tape which need to be grounded. but this is very tedious, I won't go there unless my life depends on it. #PS, its impossible to cater for every possible events, there will come a point when you MUST draw a line & do as much you can. Last edited by KenC; Tue 30 October 2012 at 22:34..
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#71
Tue 30 October 2012, 22:34
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:-) Thanks. If I make a shield of sheet metal (I have some 22ga lying around somewhere) and screw that to the panel, that should create a pretty good shield, yes? Basically just to enclose the ribbon in a box of metal that is grounded.
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#72
Tue 30 October 2012, 22:42
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That is another way to shield. I won't go there if there are more than 1 bend along the cable path. Also, having pointy screw sticking out everywhere is irritating.
Try running it without the shield & see if you need to do the extra chore. My personal preference is to have everything visible. If I can see it, I can inspect it.
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#73
Wed 31 October 2012, 00:55
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Call me crazy, but i have no pointy screws. I drill and tap everything and use bolts...
Will play around with my configuration and see what i wasn't to do.
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#74
Wed 31 October 2012, 08:50
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I would say no... But it might be a point to keep in mind if you find your having some issues. It wouldn't take too much to make a shield for this area. Tin foil...
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#75
Tue 06 November 2012, 11:04
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Well, here is my control panel, finally coming together. The cables going to the cable tray will exit the box to the right, the computer's location, and my mains power, will be to the left. Didn't really want to divide up the box quite like this, but seems to have been what was required. Now I have to cut a bunch of holes in my box for the buttons. Anyone have any suggestions for 30mm holes? Just use a 1.25" hole saw?
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#76
Tue 06 November 2012, 11:38
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An 1.25" hole saw is really 31.75mm. Check your clearance and rake of the tooth on the hole saw. You might find a 1.125 (1-1/8") might work better.
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#77
Tue 06 November 2012, 15:10
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If you are drilling sheet metal then this step drill works the best
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#78
Tue 06 November 2012, 23:53
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Actually, 30mm is a big hole, big enough to enlarge with a round file.
What I'll do if I don't want to buy a new hole saw, drill a anysize that is just under 30mm hole say 1" or 1-1/8" & file it down to 30mm. or to fit what ever you wish to poke through...
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#79
Wed 07 November 2012, 04:48
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<---owns a lot of the step bits. Perfect for panel work.
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#81
Wed 07 November 2012, 05:07
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I am going to rename Northern Industrial as Eastern Industrial. There are no stores out here in CA! Grr. I think I'm going to give the step drill bits a go and see how they do.
Looking at this one, since we apparently don't have better stores around here that have a reasonably priced set. That I've found so far, at least. Irwin Unibit HSS
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#82
Wed 07 November 2012, 05:15
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Why do you like the smooth taper better?
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#83
Wed 07 November 2012, 05:52
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Because you use smooth pressure to push it in. The step ones are "jerky" and sometimes I went one step too far if I pushed too hard for too long. You have to push them harder at the steps.
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#84
Wed 07 November 2012, 16:11
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I use smooth ones too, but could not find the image right away, its very easy to enlarge the hole once you drilled the initial one with a ordinary drill
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#85
Thu 08 November 2012, 10:20
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Thanks for the feedback. Are there any issues with the hole wandering off-center with the tapered drills? I like that the step drill has, essentially, a center guide built in. I'm presuming the tapered bit does roughly the same thing, but don't want to make that assumption and get proven wrong.
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#86
Tue 13 November 2012, 12:38
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So where are you guys getting beveled washers from? McMaster seems to have the best price, at almost .50ea. Is there a better source that I haven't found just yet?
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#87
Wed 14 November 2012, 14:00
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How many of you guys are running both hard stops and proximity stops? I am, but I'm a little fuzzy on how that logic works. Is there some type of override that lets you ignore your proximity targets while squaring up the gantry against the hard stops? Gerald alludes to Mach3 being able to do this here: http://www.mechmate.com/forums/showt...&postcount=196
But I wanted to confirm that that is, indeed, the case. To square the gantry, you override the proximity switches, pull the gantry against the hard stops, then jog to a point inside the proximity switches range, remove the over-ride, and home to the proximity switch for your starting (0,0) point. Am I roughly understanding all of that correctly? At that point, you've squared the gantry via the hard stops, and have homed to 0,0 via the proximity switches, and can go about your merry way...?
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#88
Wed 14 November 2012, 14:51
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And, to add to the complication today, discovered my stopper blocks are only 1.25" to the CL of the proximity sensor, instead of the 1.5 or so that I actually need to get to the CL of the target hole. I have a few worries about putting any kind of spacer/washers in there to get the correct off-set distance, for fear of it shifting over time as I pull it against the hard stops. Am I worrying too much about that, or should I go ahead and cut off the bent section and weld on a piece of square steel to give me the proper offset? Or just find some 1/4" flat stock, cut a spacer the proper size, drill some holes through it and call it good?
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#89
Wed 14 November 2012, 20:33
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Locktite will save your soul.
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#90
Wed 14 November 2012, 22:21
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Eric, the squaring against hard stops is done outside of Mach. Have motor drives switched off, hold gantry manually against stops, switch on drives.
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