When Layer Orientation Matters

Often when you are 3D printing the main thing you think about is how much support material your print will have, and you orient your print to minimise this – reducing material waste, print time and any manual post-processing to clean up the print. However sometimes the best print orientation for these reasons is not the best for mechanical strength, and I’ve just discovered this with one of the parts for the InMoov robotic arm I’m currently building (see the first collection of 3D prints in my previous post).

The “RobServoBedV6” part is where the 5 servo’s connect that control the individual finger movements, using screws to fix them in place. However some of the stands are splitting as I screw into them as shown in the photo above due to the layer orientation. Yes I could use super glue to fix them, but the split will just happen  somewhere else. So I’m going to completely cut the stands away from the part, and re-print just these stands in a different orientation to improve their strength. This is where the free program Meshmixer comes in very handy, and I’ve previously published a few examples of how to use it for my friends at Pinshape – just click here to find out more.

In the top right image you can see the first step of using Meshmixer to edit the STL file. I have used the Plane Cut tool to slice away the bottom plate, and then repeat the process to remove the other 2 segments which seem to be strong enough for the screws at the moment. This leaves me with the 2 stands that I’m having issues with. These can now be exported as STL’s ready to 3D print (orientation is not important here, this will be set in my 3D print software).

I’m printing these parts as we speak on my Cocoon Create 3D printer, and have used Cura to prepare the parts and get the G-code. As you can see to the left, I have oriented the parts so that the layers are perpendicular to the original orientation, meaning that when I screw into them, the force from the screw will not pull the layers apart. Super glue will hold these replacements onto the original part really well as they are printed in ABS.

If you are designing your own parts from scratch in CAD and intend to screw directly into them, keep this issue in mind. However if you’re downloading a STL where modification isn’t as easy, knowing this simple trick in Meshmixer can really help you repair and improve a part rather than trying to re-print it from scratch and potentially use a lot of support material in a different orientation.

– Posted by James Novak

Meow… 3D Printed Cat

After the stresses of getting my new Solidoodle Press 3D printer working over the last week, it’s nice to jump back to the faithful Up! Plus 2 for a simple print. This design was downloaded from Thingiverse, you can also get one by clicking here. It’s also a bit of fun taking photos of the result!

I will admit the print didn’t come out perfectly – there was a bit of a skip about half way through, resulting in a gap just below the neck. I’m not sure what caused this error, but the small amount of support building inside the cat to support the top of the head also broke at about this time, so perhaps the nozzle collided with the print and fell out of sync? No major problem though, it’s only noticeable up close, and nothing a ribbon can’t fix. You can see what I mean in the below time-lapse photos, with the support broken and angled in the 3rd image, then removed by the 4th image. But the top of the head still printed without any problems, so the support wasn’t needed anyway.

Sure makes a good gift for someone, thanks Roman Hegglin for the design!

– Posted by James Novak

New Year, New Print Errors

A while ago I posted about some problems I was having with my Up! Plus 2 3D Printer slipping throughout some prints (read the post by clicking here including how I fixed the problem). Well the issue seems to be back as you can see in the first image above. The first slip was quite small, so I let the print continue, but when I checked on the print after about 4 hours I found this lovely mess with 2 more slips.

I’m going to try the same procedure as discussed previously – cleaning the debris inside the arm that may be catching in the belt (controls front-to-back movement), and applying some grease to the silver rail which the print plate slides along. Hopefully this is just a continuing maintenance issue, and not something more complicated. Time will tell…

– Posted by James Novak

UPDATE 16/01/2015: After taking a closer look at the mechanism, I noticed a small tension clip interfering with one end of the gears. It’s just an overhanging piece of the wire, but when the print plate moves to the very back position it begins to wrap around the gear and this small overhang hits an edge of the grey plastic pictured below. I have used needle-nose pliers to bend this arm down slightly so that it no longer collides. Hopefully this will help reduce any print errors as well as the clean/grease mentioned earlier.

3D Printed Doof Doof! (Phone Amplifier)

I’ve always been fascinated with the way putting your phone into a cup or bowl can suddenly improve the sound quality and volume. Even a simple cardboard tube will work (check out this video if you don’t know what I’m talking about). Being a bit sick of having no real spot for my phone on my desk, I thought it was a good time to have a go at 3D printing something that would both hold my phone and improve the sound when I’m playing music or just when a call/text comes in. Yes it’s been done by many others, but of course I want my own unique design!

The above video is the outcome of about 4 hours of printing on an ‘Up! Plus 2‘ 3D printer (0.2mm layer thickness, <10 degree support), showing how little support material was required and that it works straight off the printer. I swapped filament colours part way through printing to create the multi-coloured effect, following on from my last post.

In the video you’ll notice the phone doesn’t really sit in place properly – I forgot to add a little rib to stop it sliding forward. However I have since glued a small piece of scrap in place, and updated the STL file to provide this feature (photos on Thingiverse). Of course I have shared this design for FREE on Thingiverse so you can print one for yourself, just click here to visit the page. As always if you make one I’d love to hear about, please share comments/photos either here or through Thingiverse.

– Posted by James Novak

Experiment: Multi-Coloured 3D Printing

Anyone playing around with desktop 3D printing has probably played around with feeding different colours through the extruder at some stage, or even using dual heads which are becoming more prevalent. I’ve certainly snipped off the filament during  a print and fed a different colour through, although there is no real control doing this. The top images are a little experiment I’ve tried with the ‘Up! Plus 2‘ where I print a 5mm high ring (image 1), re-calibrate the nozzle height (image 2), then print the same part again, only without any raft/support (image 3).  This worked well, until the software said that I could only set the nozzle height within a very small range, so couldn’t go any higher than these 2 colours (total 10mm height).

I’ve then seen the pause feature – feeling like a complete noob (considering I’ve been using this Up! software for years and never tried it!) this next experiment used a 15mm high tube, which I set to pause at 5mm and 10mm, allowing me to withdraw the filament and change colours. Perfect. Yes it’s pretty limited in that a colour can only change in the vertical axis across the entire print, but if you orient your print correctly this might just be enough. Until some of those full colour 3D printers become affordable this will just have to do. Once my Solidoodle Press arrives (looking like January now – see my post about the delays here) I’ll be curious to see whether it has this same function.

– Posted by James Novak

Finish Line in Sight

Just an update on the Mario Kart Trophy progress – today all the 3D printed pieces have been spray painted in a chrome colour, and assembly has begun. As expected the paint really highlights the layers and any flaws in each part, but without spending a ridiculous amount of hours using acetone, or the more traditional fillers and sanding, this can’t be avoided. And there’s nothing wrong with celebrating the fact that this is a one-of-a-kind 3D printed product! Plenty more araldite to go, but the finish line is in sight.

– Posted by James Novak

Slip ‘n’ Slide

For the past few days I’ve been battling with this error using the ‘Up! Plus 2‘ 3D printer. The first few layers seem to be slipping or shifting, sometimes only a couple of millimeters (which doesn’t normally warrant stopping the print), but sometimes can be about 10mm which makes a real mess. What’s even more puzzling is that sometimes it happens, and sometimes not.

After reading this thread on the pp3dp forum, I’m thinking it’s time to open it up and check the moving parts. I’ve sat and watched as this error happens and there is no noticeable skip or any sound to indicate something is wrong, but hopefully I can get to the bottom of it because I hate wasting material and time. Actually, thinking as I type, the slip is ALWAYS in the front-to-back direction, so maybe this is a good place to start… I’ll share anything I discover in case you also come across this problem. If you’ve got any solutions, please leave a comment 🙂

UPDATE 08/12/2014: I opened up the arm controlling the front-to-back movement of the print plate – there was a bit of debris in there from the belt, so I’ve cleaned this out and also greased the silver rail that the plate moves along. So far 4 prints and absolutely no slipping! If you notice this slipping problem I recommend a clean and some grease, only takes a few minutes and seems to make a big difference! Check out a future post for photos of these internal details.

– Posted by James Novak

Acetone Cleanup Really Works

I’ve written a few times now about my experiments using acetone to smooth rough surfaces (see this post about my first test of brushing acetone directly onto a surface).

This 3D print is the leaf for the center of my Mario Kart Trophy. The side pictured is the bottom side of the print, i.e. the side the support raft was fixed to. As you can see in the first photo it’s quite rough, particularly around the perimeter where the raft stopped and the overhang resulted in some loose layers. I really thought I’d have to print this again, thinking no amount of sand paper or anything else could smooth these surfaces as the loose hairy strands would simply fall off, leaving big gaps in the surface.

Enter acetone, hero of the day! Within about 1-2 minutes of brushing acetone directly onto the problem areas, the layers have dissolved and smoothed themselves out into an almost perfect surface. By using a stiff bristled brush you can actually feel the surface go tacky, and control the outcome. I’ve used acetone across this whole back side to fix up a lot of the problems – it’s really like a magic wand or blur tool in Photoshop! A must have for any 3D printers’ kit.

– Posted by James Novak

Hit and Miss

Today I began some of the 3D prints modeled for the Mario Kart Trophy (follow the full story here). Seems like most of the Up! Plus 2 printers are out of order after a massive year at uni, so it took some work to cobble together bits and pieces that would work properly.

As shown in the first image, the large base piece is continually lifting (and therefore failing) – seems the plate is off level and causing the plastic to not stick into the perforations in one corner. Auto leveling is obviously not working to compensate either. Also I’ve realised I made a bit of a rookie error with the design of this part – rather than being a large solid, I should just shell most of the internal material out and reduce this large solid base to more of a ring shape. Firstly this would reduce material (yay environment!), but also remove the large mass which shrinks and enhances this lifting effect. Experience shows that large flat solids tend to do this more often than not, so my bad! I’ll adjust the model before trying again.

But the vine prints to be stuck on the timber ring worked perfectly. I’ve left a few more pieces on the machines, so hopefully they’re humming away ready to collect next time I’m at uni. Surely that’s not too much to ask? 😉

– Posted by James Novak

Fin Printing Success

So far so good – I have printed 2 fins (to use on the heel side of the board where the most force is applied) on the ‘Up! Plus 2‘ printers. I oriented them laying down diagonally on the plate in order to fit the small size (140 x 140 x 135mm), and also for strength of the final product (layer orientation). I’m really impressed with the top surfaces, and only a small amount of cleanup required on the bottom – a bit of acetone or sandpaper should clean this up nicely. All that’s left to do is make sure the screws sufficiently grab into the holes, and then bring on the wind!

– Posted by James Novak