Predator Action Pliers Mk2

by ecoiras Jun 6, 2018
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I printed my model on a brand new dremel 3d45, and it is stuck and fused a small bit. i have been working with some spiky things to free up the gears based on the model. it is going ok and i think i will be able to get it fixed, because i dont want to print it again. i printed it on dremel's black eco-abs at 0.1 mm and 20% infill.
Great model, but it would be interesting to see some ideas to improve fusing for some future projects.


I see from the photo that the first layer is already fused, so I would first work on that. I would start leveling the bed as good as possible and then do some tests with different printing temperatures and layer resolutions. For these tests just print some calibration model or the first couple of layers of these pliers, for instance. If they keep fusing then I would try a different filament or slicing software.

If you see the overall printing quality is not that good anymore-- apart from this fusion issue-- it can also be that the printing nozzle has degraded and has to be replaced.

Another potential cause for fusion is model scaling. If you scale the model down before printing (or your slicer is doing it automatically) the gaps between parts will become so small that the parts will touch and become fused. Conversely, printing at 110% scale or higher will make the gaps between parts bigger and less likely to fuse.

Those are the things that come to mind. Hope it helps!

Thanks for the tips!
I actually succeeded in freeing up the gears and it works smoothly now! thanks!

why does this model have to be printed with the jaws closed? Can it not be printed with it slightly opened?

The STL file has been rendered from the Fusion360 model in that position, but you can open the Fusion360 file, move the parts as you want, then export to STL with your chosen configuration.

In Fusion360 you can also make an assembly with the parts and simulate motion, like here: https://f360ap.autodesk.com/courses/mechanical-assemblies-fundamentals/lessons/lesson-5-assemblies-and-joints

You know when you are taking cash out of a drive thru bank machine and you're in a sedan and everything is made for truck/van height? Would this be good enough to grab cash and your card back? I usually don't need a lot of length just a few inches of reach would help.

I would say yes, but for grabbing the card you'll need good friction and PLA/ABS/PETG make quite smooth surfaces, which may slip trying to pull the card (which is also smooth). Maybe try covering the tip of the pliers in silicone so that they grab smooth things better?

Does silicon stick to PLA/ABS/PETG? I have never tried myself.

Another alternative could be using the finger tips from a rubber glove.

Sadly my print shifted in the Y axis for some reason and i was not able to get this to work. Might try again later.

Using a Monoprice Maker Select Plus. Printing slow at 30 mm/s with two perimeters inside to out. Tried to print one and all the bearing gears fused to the gears. I printed a tolerance gauge and it barely passed the 0.5 mm test. Anyone have any ideas of how I can get my printer to get tighter tolerances.

thank you.

My first print on an Anet A8 didn't turn out. The recommendation below to check your flow rate is solid. I'd go further by printing a calibration cube for each new roll of filament: 10 mm overall, two perimeters, no top layer, 0% infill. (I keep this in the printer's SD card, with 100% flow rate and appropriate temperatures for PLA, PETG, and ABS.) Measure the thickness of each side, then divide twice your printer's nozzle diameter by the average thickness.

I used to have problems getting anything less than 0.3 mm in a tolerance test to work without needing to resort to tools. After I figured out the proper flow rates for my filaments, even a 0.1 mm gap needed just a little bit of persuasion with just my fingers to get it spinning.

I need to take a second crack at this to see if it'll print properly this time. I suspect it will.

You can try checking the following:

  • Lower printing temperature. If it's too high the plastic will flow more, spreading out.
  • Reduce flow rate. If the filament is flowing too fast you will get over-extrusion.
  • Try with a filament from another make. Different brands can have different compositions.
  • Nozzle may have degraded with use. Replace the nozzle.

It's cute but welded in multiple places. Broke trying to work it loose.

Just bought an Ender 3 and this is my 2nd ever print. Worked really well except that one of the "gear rivets" stuck to the bed and then broke off as I was prizing the model off the bed. No worries though, it still works really well. Might try it in ABS later to see if it is better than PLA. Thanks for making a really interesting model.

If you frequently have problems removing things from the bed you can try printing over masking tape, glue-stick or hair spray.

Also very convenient is a removable printing surface like BuildTak.

i printed this on a cr-10 working right off the bed. i dont know why its fusing and breaking for everyone, but i would guess either the nozzle is to close to the bed, or wrong extrusion ratios

cool design but it broke 2 mins off the printer its now on my floor in a million pieces .. seems as where all the gears get held together from the very small piece on top could use some more work for strength

I presume you used PLA filament; but even then It's very strange for it to break apart in many pieces like that. To give it more strength you can slice the thing using double number of perimeters, double number of top/bottom layers and infill to 50% or so.

But even better would be to print using PETG filament; it's as easy to print as PLA but much tougher. ABS will also give you better resistance but it is more difficult to print.

And if your printer can handle it, printing in PP will make it almost impossible to break.

bloody great model, everything moved nicely after it came off the bed, but after playing with it for 30 seconds trying to grab stuff the thin sections where the outside finger holes join up near the gears snapped, if that part was a bit thicker it would be great

the download is not posible, and error apear

Are people printing this using a brim? Just wondering how difficult it would be to remove afterwards..

printed without any brim no problem

Everything went well except for the two front jaws that fused together. Any way to salvage this?

Comments deleted.

I would probably try to drag an exacto blade through the fused seam from both sides and get as deep as i could. Then very, very carefully pry it apart. You could even heat the blade up and poke the tip in to each segment.

Well, it turns out that the gears are also fused. So this one is a no go. Oh well!

I finally went back to this thing and tried again. I was having massive issues with it fusing. I printed it 3x and they all failed. After reading these comment I changed it to have 1 wall/perimeter and it printed GREAT!

Love this thing. Thanks for the work!

This thing is too long for my 180mm round Kossel Mini bed. It would be nice to have the plunger pushed in and jaws wide open to see if that would fit. Or perhaps separating out the parts. If I scale it down the clearance between parts also scales down and it doesn't print well.

I remember GygaByte42 having a similar problem and printing it in two parts: https://www.thingiverse.com/make:500923

Predator Action Pliers Mk2

Not sure what I did wrong, it was fused at the bottom layer. I printed at 200/60 with PLA, 0.2 layer height with 20% infill, any thoughts?

Your photo shows filament tracks in the first layer are too thick. Adjacent tracks should barely touch but in your case they seem to overlap. This suggests:

  • Over-extrusion: filament is flowing too fast. Reduce flow rate.
  • Head is too close to the bed. Re-calibrate the bed.
  • Nozzle has degraded. Replace nozzle.

Temperature being too high could be also a reason for this, but 200 is ok for PLA, so I would rule that out.

I am having the exact same issue any help would be appreciated

Have a look at the suggestions for TheSneakyZebra and pingywon. Hope they help!

This is a neat design! It blows people's minds when you tell them it was printed in place & no assembly was required.

you should make this like a sword and call it " the predator action plier blade" that's what i'm doing i have a file for you to check out if you don't like it then it's fine. i'll put it up to the public when i know how to submit creations to thingiverse (i really don't know how to)

That's pretty cool!

To upload it just click on Remix it, then fill up the required fields, then Save, then Publish. Easy!

Predator Action Pliers Mk2
by ecoiras

I made this as your setting. But my printed was failed. It can't use and all of joint have been stick together. Design is same but can't use. Arms hole and pusher hole are connected with other parts and can't move. I'm using CTC Prusa i3 Pro B printer. Please help me. I like your design and I really want to get one. Please guide me.

It would be nice if you could share some photos, to try to figure out what's the exact problem.

In the meantime you can have a look at pingywon's message thread below, which discusses possible solutions you could try.

Good luck!

I printed this today, but right at 99% my Prusa i3 MK3 started crashing. You can see the unfinished bits where the crashing happened. At the end it finally lost track of the coordinates and started printing into thin air and I stopped the print. Anyone else had this happen with the pliers? Just to note: I have no fused parts, and the pliers work wonderfully. It's only cosmetics I'm missing.

lawyec i kind of agree with you

Interesting design - don’t know why I needed one, but had to print to check out the action. Works as described! Thanks for the work.....

I am so jealous of this design! It's is so smart, creative, and beautiful. I love the details you made to allow it to be printed in place, masterly done. It must have took some time to figure this out. Great Job! Thanks for sharing.

The filling pattern depends on your slicing software. Set the infill parameter to 100% to have a completely solid print if you need it to be really sturdy. Alternatively use a slicer that can set areas smaller than a given value to 100% infill, like slic3r.

This printed very well with eSun PLA+ at 215C. I still have some settings to adjust on my mono price to address stringing and some other issues, but your design is quite remarkable. Do you have any recommended guides on how to make gears like you did in something like Fusion 360 and also guidelines for making these fully assembled prints. My 4-year old loves it. Looks really cool in silver.

For the gears I used the Helical Gear Generator and the mirror tool (to make them herringbone).

To make fully assembled printable objects I started by learning from what's already there, then trying to replicate the fundamental elements. The first thing I tried to design was a single print-in-place hinge, which later became the GrabToy++. The gears in these pliers are basically an evolution of that hinge.

I normally start with some pen and paper sketches of the object I want to build, then identify "difficult" elements and focus on them adding detail to figure out how to make them work. For the pliers the first thing I designed were two gears that could print in place; with the basic problem to solve being how to hold them together so that the whole group could print with no supports. I did several iterations until I got it working. After that I had to figure out how to hold the rail that drives the gears in place, so my next model was just the two gears and a rail that moved up and down. And so on, adding more elements one at a time.

The main constraint when building something for print-in-place without support is to have every point in the model reachable from the bed going up walls that are steeper than 45º (more or less), so you can start from an already working design idea and modify it bit by bit to satisfy that constraint.

Hope that helps!

Grab Toy ++
by ecoiras

That is really cool. Thanks for the info. My son really likes it and it has stood up to play by a 4 year old for at least a week.

Really nice and fun model. Though we stress tested it yesterday and it has a few week spots there the plastic are to thin and will break after heavy usage.

Just to piggyback. Very cool model, but I too had one of the thin spots break after kids played with it. Any chance to thicken those areas up?

Printed mine last night, came out amazing! and nothing was fused, in fact quite the opposite. Mine has a lot of space between the moving parts, to the point where the jaws almost feel sloppy and the gears rattle around. i guess this was made with extra tolerance for people who arent tuned right?

Merci et bravo pour le plan qui est parfait, la pince a fonctionner parfaitement sans aucun ébavurage

Skipped over the last version and made this MK2 version last night. Its printed nice, but it was fused together. I was unable to get it moving. I guess I will tweak my settings and try again. Lovely design; real disappointing that it failed :(

Wow, it looks completely fused together! Is that ABS or PLA? I haven't managed to print much with ABS myself; lots of warping and fused parts.

With PLA maybe it would help reducing the layer resolution (0.2 or 0.1mm) and reducing the head temperature as much as you can (185-190ºC).

Also, if the head is travelling too fast it will wobble when changing directions, increasing the probability of fusing parts. You can decrease the overall printing speed by reducing the feedrate (try 50%, just to check, even if it will take double to finish the test print).

Additionally, doing tests with a model as big as this one is very expensive in material and time, so you may want to do use the GTpp_HingeSlackTest.stl model from GrabToy++ instead, which was created specifically for that. If you manage to tweak your settings so that the "0.5" hinge works then you will reduce the risk when printing a big model like this Predator thing.

Hope that helps!

Grab Toy ++
by ecoiras

Hey thanks for taking the time to reply!

Yeah I was really surprised by this outcome also.

I have printed many hinged "things" before.

The Articulated slug, the Spinner air-soft targets, just to name a couple.

I have never had this issue with hinges before.

I printed it @ .2mm/60mm print speed @ 195 (PLA) Again never had any issue. Im not sure what the hang up is but Im going to try and figure it out.

One thing. I did have to do was reduce the scale to like 89% for it to fit on my bed (I didn't think about rotating it diagonally at the time). You think there is any chance this could have played a role in the fused outcome. Even the head of the pliers were fused.

Thank you for the test toy. Maybe ill give it a try...or just try and print your thing again. It just looks so awesome!

The scaling is probably a factor here, because now we have a slack of around 0.4mm. If you print the HingeSlackTest model and the "0.4" hinge is fused then we found the reason.

When doing the design I necessarily referred to my average printer, for which 0.5mm is the lowest "safe" gap I can use without things fusing. But even then, already for the Mark1 version, I found the wiggly teeth in the jaws fused together, so the gap there is now slightly larger.

Comments deleted.

I ran the hinge test. .4 was fused.

.6 and .5 were fine and .4 and .3 were fused. I reoriented the pliers to print at 100%. Think I should be good? Here goes nothing.

Fused again! Im not sure Im going to give this another try until I figure out what the issue is exactly. See attachment. Its fused just about everywhere :(

That doesn't look good! Something is definitely not right with the printer. I enclose a pic of the underside of the Mk2 printed at 0.25mm; the gaps between moving parts should be clearly visible.

In your photo there seems to be a lot of stringing inside the holes of the shaft. Have you enabled retraction in your slicing software?

Perhaps related: I recall having very poor prints after using a filament that contained copper particles. The nozzle was severely eroded and everything I printed after that looked poorly defined and fused together. I bought another nozzle, screwed it in and everything went back to normal!

Could that be your case?

Yes I had totally forgotten about the scaling that I did. I think that might be the cause. I am printing the HingeSlackTest now. thank you!

Those fused images look like one or more of these 3 issues:

  1. Bed not properly calibrated, too close to the nozzle.
  2. Temperature of extruder or bed too high. If using PLA, I recommend extruder temp of ~200C, bed temp of 60-65C.
  3. Overextrusion due extrusion multiplier being set too high.

If that does not work that try changing the perimeters/walls to 1.