Taulman3d Alloy 910 - after several rolls....

posted 25 Apr 2016, 13:51 by Colin Bell


It's been a while since my last post, since my youngest daughter was born, so apologies for the radio silence. What time I do get though, I've spent building a new larger format Kossel Delta machine, which is now finally commissioned and printing, and also revamping my triple head Mendel. I'll do separate posts on both of these as I've learned some interesting things along the builds which I'd like to share.

Of course, not having time to blog in any detail doesn't mean that all activity stopped - babies do sleep very occasionally, and when my little treasure does, I've been able to catch up on some 'fire & forget' printing to catch up on my backlog of personal parts that required creating.

Many of the parts that I needed to create needed high strength, stability in high temperature environments and ease of machining in terms of drilling and tapping. In the past, this has always meant ABS for me, however my recent love affair with Nylons kept bringing me back to the Taulman3D range, and in particular their Alloy 910 material. I've previously blogged about Alloy 910 based on a small sampler pack I had of it, and since going out and buying several spools of the stuff, I wanted to expand on it here a little as I've had a phenomenal success with it in a variety of applications.

One of the key reasons to use Alloy 910 over ABS is the fact that it doesn't warp - not even a little bit. And that delamination issue you always get with bigger ABS prints? Forget it - you can't get this to delaminate with a hacksaw easily, so a cool draft isn't going to bother it. This makes it an ideal material to use in place of ABS on machines without a heated enclosure, which is most of my 'bot farm. The Deltas and Cartesians all work well with this material with zero modification of my usual setup - of course your milage may vary, depending on your machine, but providing you follow some basic rules below, I absolutely guarantee that you'll have no issues using this stuff.

First rule up, is your bed cover of cover of choice - previously I used Kapton tape or Painters tape either on an aluminium build surface, or a sheet of glass. With PVA glue (Glue-stick) this works OK with nylons, but I did get considerable warping. I then tried a sheet of Tufnol clipped to a cold platform, and the adhesion of Nylons to this is astonishing - it's so solid that getting the part off can be a major headache. 



As regular readers will know, I've added PEI sheets to all of my machines now, and Nylons will stick very well to this provided it's heated to around 60c. For smaller, low surface area and low density parts this is just fine, however I've now found the perfect combination for those huge 100% unfill parts in Alloy 910 (drum roll...) a heated PEI bed (60c), with a light (criss-cross pattern) layer of glue-stick on it. This keeps the part solidly on the bed for the duration of the print, and a light spritz with tap water around the base of the model following print completion, means that it can be removed easily from the bed with virtually no effort. Since using this method, I've had zero failed prints and no warping or delamination even on very large parts. The box part in the picture shown here is 170x170x170mm, and the bottom layers are 25% infill with 5 bottom layers. Try that in ABS on an un-enclosed machine...

Of course, you need to be sensible with your printed part in Alloy 910, as with any material - I've found it likes a uniform and gradual cooling from the 60c of the bed. My best practice is to leave completed parts on the bed following printing, and let the bed and the part cool naturally to ambient room temperature before attempting removal. On occasion when I've need to pull the part off to start the next print, I've seen some very minor corner warping - this issue disappears completely though, as long as you let the part cool fully before removal from the bed.

In terms of layer height and high detail, the material is as capable as most, and I've not had any complaints. The surface finish is a lovely glossy surface, and it will show up detail well, particularly when dyed with an acid based dye (such as Rit Dyes), however that's not really what I use this stuff for - most of the parts I create with it are industrial strength functional parts, not pretty display items - but I'm sure it would be capable. In terms of the surface finish, a very stable hot end temperature is required - one of my machines developed a dodgy thermistor which caused the temperatures to fluctuate by 20-30c up or down of my target print temperature of 245c, and this was very noticeable on the part. I could literally see where the temperature spiked up and down on the part as it printed due to the change in surface sheen and smoothness. This didn't detract from the functionality of the part though (and it's living happily in my washing machine as we speak!)

One thing to watch though is very low layer heights - I mistakenly started a print at 0.05mm instead of the 0.25 it should have been, and the layers looked very messy.

In terms of infill, I've had excellent results from 100% infill, all the way down to 5% - all the parts are very solid, and the less infill used obviously allows for more flexibility in the finished part. I've found that for highly flexible part requirements, using 5 shells and anything between 5 and 15% infill gives the best results for durable flexible parts. I can honestly say I've not had a single Alloy 910 part break on me either, even a replacement door hinge supporting a door weighing almost 20kg shows no sign of wear after nearly seven months use.

Another thing which I mentioned previously is that as with most nylon based materials, Alloy 910 tends to 'spider web' a little during printing, and depending on the models and how far the hot end needs to travel, these can collect on the nozzle, blacken and be deposited back onto the print. I've found that use of an Ooze shield setting, combined with a .1mm Z lift on layer changes, retraction and travel moves virtually eliminates this issue. My retraction values for my bowden machines are pretty small at 3mm (3000mm/min), so the above additional slicer settings helped dramatically. This is less of an issue in direct extruder drive machines of course, but I'm tending towards bowdens most of the time to keep my hot ends lightweight.

Drilling and tapping of Alloy 910 parts is very good - being a nylon you need to run drills and taps slowly and clear the tools often to avoid them clogging, but other than that there are really no issues. Glueing Alloy 910 is possible, using Tetrahydrofuran...which is not your average hobby shop accessory. I've actually had a lot of luck with Gorrilla brand Superglue though, it stays liquid for around 4 hours, and then over the next 2-3 hours sets like concrete and will join parts together. This is good where no flexing is required, as like all superglues, it can be strong but brittle under axial forces. My preference is to design holes and alignment guides into parts, and then use nuts and bolts wherever possible.

Clean-up is also a non issue, just a sharp blade run lightly over the surface is all that's required on most prints. This is a good thing too, as I mentioned in my previous post, this material is extraordinarily blade resistant. This of course is an issue if you need to use supports on a single material machine - removing supports was nigh on impossible without violence when I first started using this material, and I was about to build a purpose designed dual extruder printer so that I could use HIPS or PVA as a support material to get around this. However...I've had another breakthrough in this area (bit of a facepalm moment actually!) where I found that the issues I was having with my supports where down to the slicer I was using.

I'd been an advocate of the excellent Slic3r application for around three years and didn't even consider that the issues I was having with Nyons and support could be caused by the way it creates the support structures. I recently purchased Simplify3D (long story, later...) and threw a model requiring support at that and printed in Alloy 910 just to see what happened. What a difference! 



The way it created the support structures is just so far ahead of Slic3r's current algorithms, and the fact that you can add custom supports makes a huge difference in any material, but with nylons, it actually makes using supports on a single extruder machine possible. Removal of the support material generated in Simplify3d is literally effortless, and leave virtually no surface defects. It really is the best $150 I've spent this year, for support structures alone.










For those interested, here are my support settings for Alloy 910.

 

In closing, Alloy 910 is now a firm favourite material for me to use, and its capabilities continue to surprise me. If you have a need for stronger than usual, flexibility and high tolerances in heat, then I can't recommend it more highly.


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