MK5 Wade's-Style Tensioner
Description
This tensioner provides MUCH stronger grip than is possible with the default delrin plunger setup. In addition, it doesn't require the same constant adjustment the delrin plunger does. Just put it on once, and go. It'll eat anything. And it can hold with MUCH more force against the motor shaft than the delrin plunger could ever DREAM of.
This thing is a MONSTER FILAMENT EATER and will take your arm clean off if you get in the way. Well, maybe that's not true. Or maybe it is. Just don't go sticking your arms in any loops of filament while printing; I don't want to be responsible.
This is advertised as "MK5" and it is - I'm not going to make any assumptions about whether YOU are using a stepper extruder or the DC motor ... anything MK5 goes. In fact, I'll give 100 bonus internets to the first person who tries it out with the DC motor and posts some photos. Most of my photos are of a stepper configuration, but it's just because that's what I'm using.
I've intentionally tried to design this using only parts you'll have on hand and can find at the local hardware store.
The design of the tensioner is of course inspired by every variation of Wade's extruder I have seen. The design of the mount is mostly inspired by natetrue's printable MK5 ( thingiverse.com/thing:5169 ). I'd have liked to have made it a proper derivative by starting with his design, but sadly I couldn't get it to render in CGAL via OpenSCAD, even after his recent fix (it did fix the error I had gotten, and replaced it with a nastier one!).
So this is a fresh design 100% by me in OpenSCAD.
Motivation: Now that I have a stepper extruder ( thingiverse.com/thing:5797 ) and I've found a way to make it pull strongly with my weak motors ( thingiverse.com/thing:6362 ) now I need a better tensioner. The bolt-driven delrin plunger on the MK5 doesn't supply constant pressure; just constant position.
The tensioner from the Wade's style extruder seems like a brilliant design to me; a spring-pressure 608 bearing can press against the filament with a good, strong pressure, and the springs ensure it can supply pressure even if your filament isn't 100% consistent, or you have worse problems like a bent bolt or whatever.
Here's a youtube video of my first actual test extrusion with it. I've since gone on to print, and have the most AMAZING consistent filament flow I've /ever/ had. It's beautiful enough to make me weep. The mechanical noise I point out in this video vanished during my first print.
youtube.com/watch?v=54xrG96qoJM
UPDATE: (2011-03-09)
I've been printing great with two of these ever since I put it together in the first place. But I usually print with a fan on - and I think my dual extruder setup bleeds a lot more heat than a single one would, and is more confined.
Long story short, I tried a print without a fan on, and my filament pusher melted down! Well, melted UP, actually. Photo posted.
I may redesign this with a thicker base, but really I think the fundamental issue arose out of my cramped dual-heads, and can be cured with a fan, so it's not such a big deal. If it should happen to anyone else though, I'd like to hear about it - and keep a spare printed just in case!
Instructions
Other required bits:
4 springs; I am using 1/4"x1/2"x.035 compression springs which I picked up for a couple bucks at my local Ace Hardware. They just fit a M3 bolt head, something a shade thinner might be even better. You can go to the Ace, get your bolts, then just go to the springs and see what fits, if you have any trouble. If you get springs that fit the right width, the length is not too important; you can use aviation snips to cut them to size. You can also use a nut or washer to help hold them under the bolthead if you're worried they are too thick.
4 M3x40mm bolts, (x45mm or x50mm will make assembly and filament changes much easier)
4 M3 NYLOCK nuts. (my photos are normal nuts but I'm sure they will come loose someday)
-- ALTERNATIVE (not tested): 4 6x32 2" bolts, plus matching nuts.
1 608 bearing (rollerblade/skateboard)
1 m8x25 bolt.
IF you are using a narrow STEPPER motor mount like mine, or TheRuttmeister's, you may want to make sure you have 2 M3x10mm on hand to fit behind the idler block. If you are using the DC motor, you might want 4 of them to fit the motor on with.
You should be able to find all the above parts between your local Ace Hardware and your local skate/rollerblade shop. The "Play It Again Sports" near me sells the bearings for $1/ea!
This part is a bit thicker than the original, to make room for a nice thick idler block. This means your pusher gear needs to be moved up a bit on the DC motor shaft. There should be just enough room left to seat the end in the bearing. I took a photo to show the clearance I've got, which you can see on the side here. (Incidentally, the 'NOISY' sticker? That's the way it came to me from MBI, I didn't label it.)
I think I took enough photos for you to see how to put it all together. After you've got it in place, if you used the M3x40mm bolts like I did, you might need to use a screwdriver or something to wedge the idler block to the side to fit in your motor, and the filament. That's how I did it. You might otherwise make sure you put the motor and shaft in BEFORE attaching the 608 idler block, but I dunno if that'll have it's own complications.
You must be logged in to post a comment.
ScribbleJ - it's just happened to me, PLA Tensioner + MK5 = bad idea. I did some test extrusions perfectly fine, no issues. I went to heat it up for a print and noticed the whole drive mechanism drooping down towards the front, the heat from the hot end had travelled up to the top of the barrel and softened the PLA tensioner mount.
Check out the video I took: http://www.youtube.com/watch?v...
I'm going to print it in ABS and hope I have better results.
Ouch dang it . I printed one of these, got four 50mmxm2 bolts and some springs, and tried it out on my cupcake (#2219) running the old-style geared DC motor. I think my real problemo was that I never got exactly the correct spring tension. It worked great for maybe two or three prints, then the feed got really weak and erratic. I tried a couple of different sets of springs but wasn't able to fully resolve the problem. When I dsassembled it, I found that a lot of plastic dust had made its way into the drive gear. I cleaned it out but that seemed to make little difference. Changing filaments also proved extremely difficult. For now I've given up and re-installed the stock (delrin) pusher. I may experiment with this further, probably with one of the newer pivoting styles.
How do I assemble this when using a 51-toothed gear? Do I need to make use of 2x 606 bearings, it's not clear from the pictures is it this:
M6 bolt -
&
gt; 51 tooth gear -
&
gt; M6 Washer -
&
gt; M6 Washer -
&
gt; 606 Bearing -
&
gt; MK5 Drive Gear -
&
gt; 606 Bearing
When using the MK6 stepper or DC motor you don't have this issue as the motor is bolted to the tensioner assembly directly. With the geared stepper we have the mounting plate bolted to it but the plate offers no support for the bolt/gear assembly.
Thanks
Installed my copy this weekend, it mostly works great. I'm using an older-style Kysan DC gear motor on it, which mostly works OK-- but two of the screw holes are too close to the heads of the spring-screws, so the cheese-head 10mmxM3 screws won't fit properly there. I've left 'em off for now and will probably get countersunk heads some time soon for proper clearance.
Augh, my springs are terrible, downgrading to vanilla MK5 with geared stepper till I get some new ones...
I've added this to my big list of ToM upgrades at http://www.thingiverse.com/thi...
I've been using one or two of these every day and they are working great for me -- just wanted to post an update.
I haven't tried printing again without a fan though, just for the record. :)
I was just wondering... Is there any reason this thing wouldn't work with 1.75 mm filament? Has anyone tried it yet? I was planning on switching to 1.75mm as soon as my 3mm feedstock ran out which is still a few months away :[
Well, I was having trouble with my tensioner on my Mk6 stepstruder. So I had this laying around, which I printed a long time ago, but was hesitant to put on. I finally put it on because of the problems I was having and wow, this thing is so worth it. Works great. A must if you are going to use the reversal plugin too. I don't ever want to see that stupid delrin plunger ever again. As you can see in my copy, I am printing another one up, because the one I have installed works fine but it looks kinda ugly.
It's easy to miss in the giant wall of text, but I made an update yesterday and added a photo of my melted filament pusher. I think this is mostly due to having a cramped space with two print heads, but I usually print with a fan on - and you might want to also, just to cover all the bases.
Where do you get M3 x 40mm or 45mm or 50mm bolts? My ace doesn't have anything above a 20mm. I just got a shipment in of most sizes M3 between 5mm all the way up to 35mm, 100 of each from bolt depot, but they didn't have any M3's above 35mm.... I look online, but all the ones on Amazon say currently unavailable. There are a few at specialty shops, but the prices are super ridiculous. I found one place where I could order them online, but you have to by at minimum 500 of em and I have to wait for them to call me or email me with the price. Anyone got a suggestion for a good online bolt vendor?
The only possible improvement I could thing of was to add a dust remover like this one: http://www.thingiverse.com/thi...
I uploaded it here: http://www.thingiverse.com/thi...
This is my first upload so let me know if people have problems with it.
Wow... You need a Flattr account, this design is amazing. I didn't think filament consistency had an effect on the print quality, but the prints are soo much better now.
I've been trying all day to get this to print in PLA. Which I have no experience in printing in that material. Can this be printed in ABS? I figured it needed to be in PLA for the strength, but I think I see some in the copies printed in ABS.
Scratch that, got it working... for the most part with PLA. Having the two separate files worked much better for me.
I still have one issue though. On the mount, the little tab that sticks out, well because of the indentation which I assume is for the bolt head, it starts warping when I get about 15 layers into the print. I know my profile isn't the best, but it is such a flimsy piece in the beginning, because o
f the bolt cap hole, it doesn't have enough to grab on to the build surface. I have tried scrubbing the area with isopropyl alcohol, lowering my temperature, decreasing my bottom height, increasing my carve. I know if I can just get it to stay put until it reaches the top of the socket cap screw hea
d indentation, everything would go fine. But I just can't get it.
Would it interfere with anything if I modified that area to include a triangle connecting that area to the rest of the print for the first few layers? Or would that get in the way of other hardware?
Can you upload a seperate STL file for each part? I had some problems with the top bit of the large plate and want to print only that bit again.
Excelent design, nice and simple. This is what I'm going to be using to upgrade my extruder to stepper, but just one thing, do you think you could add mounting holes for the mk3-mk4 hot end? I'm sure there are a lot of us cupcake owners that have them.
Awesome prints, benipk and billyzelsnack!! Thanks so much for sharing the photos.
:)
I ended up drilling a countersink area for the top/bottom motor screws. Now the M4 tensioning bolts fit. I have them flipped with the nuts on the spring side.
I'm still having some sort of issue with motor shaft bearing. Performance is great during tests, but during prints not so much. Just removing the motor shaft bearing altogether seems to work great though.
The biggest "problem" with this upgrade is that I now have nothing on this machine to fiddle
with while mindlessly watching a print!
Ya'll may have seen my dual-stepper layout. When I am using two steppers, the bot can pick itself up off the table without stripping the filament or skipping.
But I don't think I need THAT much power. I'll be doing more testing tonight but so far it seems like this mod, the Wade's-style tensioner, takes enough friction off the filament that I have plenty of power with a single stepper. I'll report more soon.
It's working well, one observation is that I think the restart lag of the extruder has been reduced. Before with the stock tensioner there was always a long delay before the filament got back to the right speed after the motor started again, this seems much reduced now, making for far nicer prints.
I think the short story is "with this Wade's-Style tensioner, having 2 steppers is complete overkill."
http://www.thingiverse.com/thi...
Here's a little something I threw together to help in the testing, that might be more generally useful to people.
Ok. I'm extruding with a DC motor now. Though with no springs, since my screws are too short, and top/bottom rear tension bolts just floating, and even no motor shaft bearing. When I first ran it the tension bearing did not spin. I think the tension bearing might of been rubbing against the motor pinion filament grabber thing.
I loosened the tension screws completely and then tensioned the (top/bottom front) screws until it was extruding. It did not take much at all. Now I wonder if the Wade extruder tension thing is way more heavy duty than requirel and more a monster truck filament pull competition.
Ok. I think I found a problem (at least with M4 screws) when using the DC motor. The top/bottom motor mounting screws for the motor interfere with rear top/bottom tension screws.
Later tonight I'm going to try another hardware store and see if I can find the longer M3's and maybe all my issues will go away.
I'm in the process of putting this together right now. While at Menards I thought you must of meant M4 screws since that's all they had in the longer lengths, but now that I am assembling it I can see that you probably really mean M3 since the nut are too small to capture a M4 nut.
Another thing that I did not realize is the value of the longer bolts. You mention that they are for when you change filament, but I just glossed over it. Now that it is in front of me it is quite clear.. I shoulda got the longer bolts! haha.
Just a note, the compression spring selection at Menar
ds and Lowes was pretty poor. True Value had them, but too long. I ended up getting longer ones and cutting them in half.
No M3's. Though Iowa really isn't the metric capitol or anything. I ended up getting M4x50's. I'm using them in the top/bottom front as usual (except reversed, nut on right side) The rear screws hit the top/bottom motor mount screws, but I shoved a M4 into each without a nut to act as an alignment guide.
Seems to work. At some point I'll maybe put together a derivative that works with two centered M4's.
Nice! Now this makes sense, the delrin plunger is fine, so long as you are attentive and listen very closely during printing. With this baby in place you will not have to worry about slippage ever again, and also you can now dial in the right amount of grab without over tightening and stressing the motor.
I have heard what you have been going through and the final product is truly the manifestation of simplicity driven by inspiration. Kudos!
Now to print mine!
Ok so I printed too early so I have version 1 and 2, but need to print V3 (or whatever the latest is).
&
amp;gt;:o
Just glad you like it! Any version is likely to work; the earlier ones would have required an M8x15 (m8x16 that my store carries is close enough) and probably a bit of dremeling.
The final version I'm using everything fits just as printed, only dremeling/drilling you should need is to make sure the holes are all clear. The idler block was also widened from 15mm to 25.
I really cannot describe the awesome power of this vs the plunger bolt that comes with the MK5. It's
night and day.
I've been wanting to make some upgrades to the printable MK5 for a while, but was having the same problem trying to bring it into OpenSCAD. This not only gives me a good starting point, but also gives me some new ideas for improvements.
You might want to make a little window through the side opposite the idler, so that if you get any of the drive gear clogging up with filament you can floss the hobbing on the fly...
It's an option in my parametric version now. It got done in the end! You can even adjust the angle of it with a parameter if you want to move it up out of the way of a stepper motor.
Brilliant! It will be done -- assuming I can make the bridge. :)
More from ScribbleJ
What holds the M8 bolt in? Sheer tension? Perhaps filing the holes for a neat fit was a blunder
â¦