Author Topic: A fix for the shakes.  (Read 2625 times)

Offline ddmckee54

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Re: A fix for the shakes.
« Reply #15 on: March 14, 2018, 05:13:39 PM »
Well, this is embarrassing, I was printing ellipses when I should have been printing circles.  I knew that my X and Z axis' were off by about 2% and that my Y axis was off by about 6%.  I also knew that Slic3r would allow me to either scale X, Y, and Z uniformly, or to scale only one axis at a time.  So I came up with a clever plan M'Lords.  I would scale the X axis to 98%, then scale the Y axis to 94%, and then scale the Z axis to 98%.  I ASSUMED that this would then give me a dimensionally accurate part and merrily started printing some of the required parts for this soldering jig.  Ummmm.... not so much.  I spent many hours last weekend printing 20mm cubes and varying the scaling factor before I tumbled onto this fact, Slic3r allows you to scale a single axis, but when you do this it always starts with the original model.  The selected object on the screen may look like it is being re-scaled multiple times, but that is not what is actually happening. 

Well, NUTS!!!  I was going to have to get into the Arduino code to modify the steps/mm settings of the axis.  I have been trying to avoid this since I don't have the files for my version of Marlin.  I didn't want to break my printer any worse than it already was.

Then I discovered the M92 command, at least I think it's M92, I'll have to double check that when I get home tonight.  Anywhooo, I was already doing several other things in the startup section of the g-code file, so I added a line that gets included in every g-code file that Slic3r generates which sets my steps/mm.  Now it's job done, I'm currently printing 20mm cubes with dimensions of 20.030mm x 20.030mm x 19.968mm.  I can probably tweak the steps/mm settings to get a little closer if I REALLY want to.

I know, I know, without pictures this is worthless - cut me some slack.  I left the memory stick containing the pictures hanging out of my computer at home.

Don

Offline ddmckee54

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Re: A fix for the shakes.
« Reply #16 on: April 11, 2018, 10:26:00 PM »
Finally getting back to this little project, life got in the road - the slings and arrows of outrageous fortune and all that.

I've done some more design work, printed some prototype parts and I am doing some re-design.  I got both the front and rear soldering iron clamps printed along the solder roll holder.  I had to scrap them and re-design the clamps, I realized that there was no easy way to get the soldering iron into/out of the clamps other than prying the clamps open and threading the cord through both clamps.  I've also got the first version of the solder feeder printed.  I'm going to have to also scrap it because it won't work with the latest version of the soldering iron clamps, it does a great job of feeding the solder though.  The solder feeder is based on a 12mm, 20 tooth 3D printer extruder drive gear with a 5mm bore.

There's a lot to consider when designing the parts for 3D printing, especially when that part has multiple tabs at 90 that are all load bearing.  A part that looks good on the screen might just blow apart when you try putting a 3mm nut into a press fit pocket - DAMHIK.  I should have a usable part within a couple of days and I'll get a family photo when I've got something that works. Or at least parts that don't break when I  try bolting them together.

The rack and pinion for the soldering iron advance/retract is designed, at least the Mk. I version is designed.  I'm hoping to get it printed within the next couple of days to see if it will actually work.  I'm kind of anxious about that particular bit of hardware since it will be the first time I've done any work with gears, let alone 3D printed gears.

Pretty soon I might even be able to answer my own question as to whether or not you can 3D print usable dies for a tube bender, since I need to put a 45 bend in the solder guide tube.  I'm designing the solder guide around 3/32"OD K&S aluminum tubing with a 0.014" wall.  This will give me around a 1/16" ID which should allow plenty of wiggle room for 0.030" solder.

If I remember it, I'll get an updated version of the 3D PDF file when I get home tonight.  (I'm an old fart and my rememberer doesn't always work that well, but my forgeterer works just fine.)

Don

Online zeeprogrammer

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Re: A fix for the shakes.
« Reply #17 on: April 11, 2018, 10:51:59 PM »
Still watching and glad you're continuing to make progress.  :ThumbsUp:

Sorry to hear about your mom.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline ddmckee54

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Re: A fix for the shakes.
« Reply #18 on: April 12, 2018, 04:41:46 PM »
Okay, I got's pictures and stuff, see attachments.

The first attachment is the latest 3D PDF file, we've already gone over how to open it up.

The second attachment is a picture of some of the parts that didn't make the cut for one reason or another.  In the first row, next to the ruler, is what I am calling the Pinion Mount.  If you look closely you can see where the tab popped off when I tried to insert the 3mm nut.  In the second row, from left to right, are the Front Soldering Iron Clamp, the Solder Feed Assembly, and the Rear Soldering Iron Clamp.  The feed assembly, while it worked just fine, did not clear the re-designed soldering iron clamps.

The third attachment, second picture, is a shot of the Pinion - hot off the presses as it were.  I've got to work with Slic3r on my first printed layer.  It's smooshing too much and I get a lot of flash that has to be cleaned off the part.

The last attachment is a family shot of all the parts in all their glory.  I know that it's a crappy picture but it was late and I was tired - deal with it.  Everything goes together, not well, but it goes together.  The rack and pinion work better than I hoped they would, it's the knob that I'm having trouble with.  I've got to work on my tolerances when I'm printing, I tend to not allow enough.  I end up with an interference fit where I'm aiming for a sliding fit.  I also don't usually allow enough for the way the slicer determines the top of the part.  For instance I usually print a 0.3mm first layer with 0.2mm layers.  If the part is 10mm thick, usually the slicer says 9.9mm is good enough, but sometimes it goes to 10.1mm - still trying to wrap my head around that one.

Don

Offline ddmckee54

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Re: A fix for the shakes.
« Reply #19 on: April 14, 2018, 04:48:45 AM »
Good news/Bad news:

The good news is that I played around with the clearances, then reprinted both the Solder Drive Mount and the Solder Drive Knob.  I got a reasonable fit, one that I could mostly live with.

The bad news is that the stinkin' thing don't fit.  One of the walls of the Solder Drive Mount only had minimal thickness, 1-1.5mm-ish, so I beefed it up to about 2.5-3mm.  Yup, I beefed it up right into the soldering iron.  Now that I know where to look I can see the problem on the 3D model.  Oh well, Kay-Sarah-Sarah and all that.  I've got to move the Solder Drive Mount a couple of mm away from the soldering iron, which will move the solder centerline.  The bottom line is that I've got to re-design and re-print at least 3 parts.

I've got to re-design the top half of the front soldering iron clamp because it's got a hole printed through it for the solder guide tube, on the solder centerline.  I've got to change the Solder Drive Mount because it's too thin to properly support the Solder Drive Knob - lets it flop around under pressure.  I'll make a pocket for the mounting nut at the same time.  Finally since I'm changing the thickness of the Solder Drive Mount, I've got to modify the shoulder on the Solder Drive Knob.

Right now, it's late and I'm pissed irritated, I'm gonna watch a little TV then go to bed.  No pictures tonight, when I get this straightened out I'll take a Family shot of what I've got printed, including the soldering iron and solder roll.

Don
« Last Edit: April 14, 2018, 04:53:08 AM by ddmckee54 »

Offline ddmckee54

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Re: A fix for the shakes.
« Reply #20 on: April 19, 2018, 07:11:11 PM »
Well, I've got a couple of pictures to share.  The first attachment is the family shot of everything bolted together.  Looks nice, doesn't work - at least not the solder feed, but it looks nice.  It's sitting on my printer build platform which is 8" x 8" so that will give you a size reference.  The second attachment is the current Mk. IV version of the solder feed drive.  It also looks nice and it also doesn't work properly.  I tried something new, I tried to export a 3D PDF of just the layers of the 3D model that had the new roller design on it.  What I got was EVERYTHING, including the original design.   Can't tell where the old version stops and the new version starts so I'm not going to attach that.  I'm on the Solder Feed Drive Mk. IV, and I'm still not happy with it.

Mk. I - This version interfered with the soldering iron, it had to go.

Mk. II - This version didn't interfere with the soldering any more.  However, I found out that I didn't have enough support and the knob would flex in the mount allowing the drive gear to slip on the solder, so this version had to go.

Mk. III - In this version I redesigned the shaft of the knob and the mounting bracket that it fits into.  That eliminated the flexing of the knob.  But the drive no longer works reliably, the drive gear did not put enough pressure on the solder to pull the solder off the roll.  I also have determined that my parts fit issues have been in part due to over-extrusion.  I had increased my extrusion rate to try and compensate for a gap between filaments in thin walls, under 2mm.  I have since switched to the Prusa version of Slic3r which seems to handle thin walls better, or maybe it's just that I've been designing my own stuff and I avoid walls under 2mm thick.  I've also decreased my extrusion rate by about 6%.  This helped on the smooshing, flash, and extra plastic that I was getting on the first layer.  I think the overall fit and appearance of the parts has improved too.  Any how, on to the Mk. IV.

Mk.IV - The current version has an adjustable roller that I thought would allow me to put enough pressure between the roller and the drive gear to keep the solder from slipping, but it turned out not to work quite right.  It feeds a short piece of solder just fine, but it won't pull the solder off the roll.  I think the roller mounting bracket is flexing enough to allow the solder to slip.  Apparently I didn't learn my lesson with the MK. III.  I even re-designed the mounting brackets to put more beef into the roller mount.  However I'm not sure that even my new design would work.  Oh well - on to Mk V?

While I was driving into work this morning I had a brain fart.  My daily commute is about an hour each way so it gives me some time to think.  I like the idea of an adjustable roller and I want to keep it, so I'm thinking maybe I should mount the roller on an adjustable lever.  I can use a bolt to clamp the lever down and adjust the pressure.  I'll probably get less flex than I am now.  The big problem is that I'm already trying to put 10 pounds in a 5 pound sack and this is just trying to put more junk into an already limited volume.  I'll need to pivot the end of the lever somewhere.  I can't go back towards the solder roll because that will just make feeding the solder MORE difficult.  Going to the front with the pivot is about my only option, but that will make printing the solder drive mounting bracket more difficult.  Not impossible but it means printing with support where I don't use support on the current design.

'Til next time,
Don

Offline ddmckee54

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Re: A fix for the shakes.
« Reply #21 on: April 20, 2018, 09:27:39 PM »
I think we've got a winner!

The Mk. V solder feed drive looks like it could just work.  I haven't tried to pull solder off the roll with it yet, but I've got a good feeling about this one.  It just feels solid, if you know what I mean.  I designed a roller on an adjustable lever arm, like I described in my last post.  Over the weekend I'll bolt everything back together on the soldering iron and try pulling solder off the roll.  I'll post some pictures and let you know how it worked on Monday.

I've found that I need to loosen the tension or the roller when I thread the solder through the feeder.  That's no big deal, because it's pretty much standard industry practice to release the pressure on the rollers when re-threading a machine.

Now that I'm pretty sure I've got a working solder drive, the next hurdle will be to build the tube bender so I can make the bend in the solder feed tube.  After that I can see if the Mk.V will push the solder around the 45-ish bend in the tube and through the 3" - 4" length of the tube , otherwise it'll be on to Mk. VI.

Don

Online b.lindsey

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Re: A fix for the shakes.
« Reply #22 on: April 21, 2018, 01:14:56 PM »
Was just checking in on your progress Don and that is quite a rig you have come up with. I like how you have used the 3D printing in this project too. It seems like you are getting close now, just keep after it :)

Bill

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Re: A fix for the shakes.
« Reply #23 on: April 21, 2018, 02:06:23 PM »
Looks like you're making great progress.

I see you're driving the solder using the same/similar method used to drive the plastic in the 3D printer.
For the 3D printer, the mechanism not only has to pull the plastic from the roll but needs force to extrude.
In this case, you only need to pull the solder off the roll.
I don't think it matters, but if you're unhappy with the serrations in the solder caused by the toothed wheel, you could probably get away with smooth hard rubber pinch rollers.

Apologies if you've already considered this.
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Offline ddmckee54

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Re: A fix for the shakes.
« Reply #24 on: April 22, 2018, 06:06:26 AM »
No pictures yet, computer software issues at home - going to have to fire the IT department.

However when I bolted the Mk. V up to the rest of the parts it passed the first test - it pulls solder off from a full 1/2 pound roll of solder.  That's the biggest roll I wanted to handle so it's on to the next hurdle, seeing if the Mk. V will push the solder down the guide tube and around the corner.  Gotta' get the tube bender built, but that's my other build and I'm workin' on it.

Zee - The solder drive gear is an E3D Mk. VII extruder drive gear, I figured "Why re-invent the wheel?"  Plus now I've got a couple of spares if my printer extruder drive gear craps out.  The Parts department loves it when they can share spare parts between multiple pieces of equipment.

Don

Offline GailinNM

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Re: A fix for the shakes.
« Reply #25 on: April 22, 2018, 05:55:23 PM »
 :ThumbsUp: :ThumbsUp:
Great progress Don.
I have been following along since the beginning of the thread. I am working on a similar but different project to suit my particular difficulties.

I had a stroke about 6 years ago so my hands don't always do what I tell them , but that is still improving.  While in rehab they gave me a tablet and told me to draw the letter "A".  Try to keep it on the paper. It took a few days.   But the biggest problem is I started to lose my vision about 20 years ago.  As of  the end of last year I was declared legally blind.  So all soldering is done under a microscope or video magnifier.  Workholding and positioning is very important. That is the thrust of my current efforts.

I will be here for the duration  Good luck on the project and successful outcome.

Gail in NM

I would like to be the kind of person my dog thinks I am.

Offline ddmckee54

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Re: A fix for the shakes.
« Reply #26 on: April 23, 2018, 08:48:25 PM »
The soldering iron Family photo that I told you I'd get is attached.

I'm really starting to think that I can actually get this thing built.  Six months ago I, because of the dimensional issues I had when printing I wasn't so sure I could do it - at least not with this printer.

I think I'm finally getting the X and Y axis dimensional issues beaten into submission.  I'm just going the have to accept the fact that you can't print a partial layer, so +/- half a layer of the actual dimension is about as close as I can expect the Z axis to get.

The tube bender build is progressing nicely so now I'm going to have to give some serious thought as to what goes in front of the soldering iron.  An X-Y positioning table of some sort with clamps to hold the work steady at the very least.

Whatever it is it will involve 3D printed parts and probably a goodly amount of that brown non-homogeneous organic material that Jo dis-likes so much.  If for no other reason than it makes such a lovely thermal break.

Don