Awesome Overhang fun

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So I’m printing some camera clips on Una, my Ultimaker (seven years old this year). I forgot to ask for support for the print. I needed support because the top half of the clip just sticks out into the air. If I’d asked for support the gap on the left of the picture above would have been filled with removable printed bits that support the “ledge” that is being printed.

However, when the print finished I was impressed that even with the lack of support I’d got something that is probably usable. You can see the dangling loops of filament at the bottom of the ledge but after a few layers they had bunched together enough to get enough material to complete the print.

I’m not proud of my inability to specify support when a print needs it, but I’m very proud of the way that Una coped without it.

Slow and Steady Prints the Best

What failure looks like…

What failure looks like…

I’m doing some 3D printing to make cases for air quality sensors. I know that 3D printing is one of the slowest way to make a case and I’m going into Hull Makerspace to play with their laser cutter this week to see if I can make stuff much more quickly, but I happen to have a 3D printer and it seems sensible to use it. However, it has not been plain sailing….

I’m using some new filament, and when you do that you have to learn the right temperatures to work with it and how friendly it is. The new stuff has not been very friendly. Mainly because it didn’t want to stick to the print bed. The print bed is the surface upon which the printed object is laid down by the print head.

When 3D printing the most important stage of the print is putting the very first layer on the print bed. If this doesn’t stick, everything else is going to end up a like a ball of wool (see above). And I couldn’t get the new filament to stick properly. Even after spending ages adjusting the bed level and height, changing temperatures and adding adhesive I’d still get terrible results.


I’ve found that the key to success is to print the first layer very slowly, giving it time to take hold. The snag is that slow printing takes ages. Fortunately the latest versions of printing tools have come to my rescue. The latest version of Cura (the magical tool that I use to convert 3D models into printer commands) lets you set the speed of the first layer print.

There are so many print settings now that the settings process also contains a search function. If you search for “speed” you can find the initial layer print speed settings as shown on the left.

If I use the settings shown I get quite astonishing levels of print adhesion. In fact I can do away with glue completely and print onto smooth glass, which gives a fantastic finish.

I’ve now gone from having a problem getting the print to stick to having a problem getting the printed piece off the printer. But I’m very happy with that.

Creating 3D Printed Text Masks


I’ve been refining my light printing technology, based on the “Do it for Josh” light (which is still available by the way). The first version used a printed mask and transparent letter inserts that were stuck inside it. It worked OK but it was a pain to assemble and the letter inserts kept falling out.

So I’ve designed a new version in which the letters and the masks are all printed in one. The clever (I think) bit is that I print the first few layers using transparent filament and then switch to solid during the print. I quite like the effect, and it means that I don’t have to assemble anything.

If you’ve got a 3D printer you might like to experiment with changing filament during the printing process, most printer firmwares have an option to do this and you can get some quite nice effects.

Hot Fingers


I’ve been doing a lot of 3D printing lately. What with josh lights and everything. Today I thought I’d replace the print nozzle on Una, my 3D printer. Turned out that hardest part of the process was finding the replacements that I’d rather sensibly bought a while back. I looked where they should have been and didn’t find them. This triggered a huge hunt all over the house, loft and garage. All to no avail. So in the end I resorted to going tack to where they should have been and used the ancient old trick of looking properly. And of course they were there, tucked in the bottom of the drawer. Idiot me. But, on the bright side I now know where lots of things are that aren’t 3D printer nozzles.

Replacing the nozzle on a 3D printer is made much more exciting that it might be by the way that you have to do it when the print head has been heated to 200 degrees centigrade. Fortunately I’ve done this before, and consequently no longer have any nerves in my fingers so, in no time at all, the old head was off and the new head on. I think the prints look better, which is a good thing.

Making a lightbox


Yesterday I had a bit of a cold. Today I seem to have got all of it. So I feel rubbish; what better time to do something silly. I've decided to make a letter light for number one grandchild. See if you can use your skill and judgement to work out her name from the above picture. 

I found a really nice design on Thingiverse for letter boxes, but I would have had to stick them all together and make a box to put them in and so on and so on. No fun. So I've written a little Python program that runs inside FreeCad to grab the STL designs, convert them into FreeCad shapes, stick them all together, create a backplane for the light box and then a plinth to put them in. I've even added a hole for the power socket and wall mounting holes. 


I've discovered that I can just handle a six letter word if I print diagonally on Una my Ultimaker original - still doing a sterling job after six years. The light boxes are 30mm in size and a perfect fit for some waterproof neopixels that I had lying around. 

I'm printing out the bits and fitting them together at the moment. I'm going to make a modification that lets you make a box with multiple lines and then when it's all working well I'll put the code up on GitHub.  

3D Printing "Snap Off" Components


I'm putting together some Hull Pixelbot kits and one of the components that I need is a set of spacers to separate the circuit boards from the perspex base and top. You can of course buy these, but I'm too mean to do this, and I happen to have a 3D printer that I can play with. 

I wanted to print all the spacers as a single item, so that I don't have to count them into each kit. One way to group a bunch of components together is to print using a "brim". A brim extends around the base of a piece and helps it stick to the printer base. If components are placed close together the brim merges to form a single sheet which holds all the components together. This works well but it can be quite a pain to then peel the brim off the items once they are printed, particularly if the items are small, like the washers above. 

The solution I've come up with is to print a single layer which sticks all the elements together,  followed by another layer on top of that which stiffens the support layer. If you look at the picture above you'll see that the top layer doesn't go all the way up to side of each spacer, there's a tiny gap around each one. This lets you "snap" the spacer out of the base.

One other trick that I'm using with my spacers is to print the first layer of the spacer with a hole which is slightly smaller than the others. This means that the spacer will grip onto a bolt, so that they are a bit easier to fit onto the robot when you are building it. 

Get Cura 2.1.2

Una, my four year old, hand built, 3D printer, just got a lot better. I've just downloaded the latest Cura slicing program and used it with the default print settings. And Una has produced some of the best looking prints I've seen for ages. Well up to the standard of the Ultimaker 2;s at work. The new Cura defaults are a lower temperature than I normally use, with a cooler heated bed too. But they work really well. There looks to be quite a few changes in the way that the slicer works and the user interface is now very slick.

The only thing I'm missing is a way to tell Cura that the print head on Una is a rather strange shape, and not the default. If I can't do this it means that its hard to print multiple objects on the platform because the fans will crash into parts already printed if I'm not careful. However, it's a small price to pay for such lovely print quality.

The great thing about Cura is that it is free and it works with a huge range of 3D printers. If you haven't got it, you should get it. If you have got it, you should go for the latest version. 

3D Printing at Cottingham WI

I've done talks at Cottingham WI before. Great fun. I was invited back again this year and, rather than talk computes I thought I'd take along the 3D printer and print some cheese.

The printer behaved herself impeccably. I love the way that I can throw my Ultimaker into a blue IKEA bag, take her somewhere and have her just work. Anyhoo, everyone was fascinated. Best question of the evening: "Why is it called a 3D printer?"I really don't know. You can't really call it a printer as it does't print as such. It makes things. I quite like the name "fabricator", but the world seems to have decided its a printer. So that's that. 

Thanks for inviting me and being a great audience folks. And I got to judge the chocolate brownie competition, which entailed sampling every one. Which was lovely.

Printing Green Cheese for 100% Students

I've been giving awards for the best performance in First Year labs and exams. Last week I gave awards to the top five or so exam scores. When it came to the practical work I had a bit of a problem, what with ten students getting 100% in the work - which is awesome by the way folks. 

Anyhoo, it means that Una the 3D printer has been busy for a large chunk of today dropping out perfectly formed pieces of green cheese for next Monday's lecture....

Print with a Brim

Three pigs and a crocodile. (sounds like the name of a musical). 

I'm keeping the 3D printer busy printing tiny 3D animals They are all going to fit into a puzzle design that I found on Thingiverse.  I'm going to use different colours, including a rather nice pink that I've got for the pig. 

One thing I'm doing to massively improve my prints is to print with a brim. This is printed as part of the base of the item you're printing. After the print you trim it off. This is known as a brim trim.

Anyhoo, brims make a big difference to quality. They are printed from the outside in, and give your printer plenty of time to sort itself out before the actual model is printed. They also provide a bigger sticking area, greatly reducing the amount of "curl" that you get on the corners of prints when they lift up from the print bed as they cool. 

I use Cura to do my printing and the Brim is one of the platform adhesion options. The other one is Raft, which I don't use much. You can set the size of the Brim too. 

This is what the Brim looks like in print preview. I suppose I'm using a tiny amount more filament than before, but I'm much, much happier with the prints I'm getting.

Printing in the Air

I've been doing a bit of 3D printing recently and I've had a need for some lens caps for, er, lenses that I seem to have bought recently. I found a design on Thingiverse that looked promising, downloaded it, sliced it and Una, my lovely if rather tempestuous 3D printer, refused to print it properly. 

To be honest, I've been expecting problems. I made the mistake of saying to Peter last week that I've reached the point where the printer "just prints" these days. At the time I said this I worried that I may have spoken too soon. And it looked like I was right. 

The print just refused to stick to the printing bed. The filament just went out into the air and all over the place. This is usually a symptom of poor alignment of the print head and so I spent a non-happy half an hour today getting the bed height precisely positioned. And it still didn't work. Very annoying. 

And then I noticed something odd about the print design. It seemed to be hovering in the air a millimetre or so above where it should be. Turns out that the printer was set up perfectly all along and the fault was with the design itself. I've found a different, less levitated, one and it prints out pretty much perfectly. Oh well, another good lesson hard learned....

Printing Tiny Robots

I've not done any 3D printing for a while. Then, earlier this week Peter showed me some things he'd been printing and they looked rather nice. And today on Twitter I saw a link to a tiny articulated bot that looked interesting. I like designs which print all as one. The legs, arms and head are intended to be separate items which stay fitted together because they are made that way. The original model had a print time of four hours, so I scaled it right down to speed things up and get a print time of an hour or so.

I was a bit worried that this would mean that the different pieces would fuse together into a single block but with a bit of careful twisting I managed to free of all the elements and I now have a tiny figure to help me with my breakfast cuppa. 

Robot Recovery

Last Wednesday my balancing robot kind of overbalanced, leapt off the desk and shattered on the floor. You can see the awful damage here. At the time I said that all I'd have to do is design some replacement parts, print them out,  and I'd have him back on his wheels again.

So I have.

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These are the FreeCad designs for the two plates that were broken. I did some careful measurement, wrote some Python to do the designs (it's a strange way to work, but I like it) and then printed them out and put everything back together. And it all works, which is nice. I think the new pieces are quite a bit stronger than the old ones. And if they break, I can just change one value in the program, run it again and print out some thicker ones..

RGB LED Panel Magic

Some time back I got some of these SparkFun LED panels. I hooked one up to an Arduino and got impressive results, although just driving the pixels took pretty much all the power that the Arduino had. I had this plan to use a Parallax Propeller chip or maybe something from Xmos to create a fast moving animated display. But I never got around to it.

Then I found out about the SmartMatrix Shield for the Teensy 3.1 device. This sorts out all the wiring and power supply issues (all you need is something that can spit out 5 volts at a couple of amps). The Teensy is a quite amazing machine. It pops a 72Mhz processor with 64K of RAM and 260K of ROM onto a platform the size of an Arduino Pro. The development tools integrate straight into the Arduino environment and the deployment to the device works wonderfully, far better than a "proper" Arduino.

TodayI set about building my display. Everything fits into an 8 inch picture frame that I got from HobbyCraft.

You can see it all above. The Teensy and the SmartMatrix Shield are at the bottom of the picture. I've also attached an SD card and an IR receiver that allows remote control of the display.  There's a really good set of step-by-step instructions on the AdaFruit site. I designed and printed some corner brackets to position the panel inside the frame, you can get them from Thingiverse here.

The Teensy runs the Aurora software which is completely wonderful. it produces some really lovely displays. I've had to hack it slightly to get it to work with a remote control I happened to have lying around. The display is excellent, and photographs just can't do it justice.

One other nice surprise was that I did all this on my old Surface Pro that is now running Windows 10. It took all these strange programs and usb devices in its stride and just worked. I'm looking forward to adding some more visualisations and searching down some animated gifs to play on the device.

Seventy Degrees Print Bed for Perfect Prints

I've been doing a lot of 3D printing lately. For some reason I've got it into my head that it might be neat to sell little 3D tags as part of the Red Nose Day event. Which means I have to print them. Una, my lovely 3D printer has been misbehaving a bit of late, prints have not been adhering to the print bed very well and their undersides have been a bit rough.

Last night at C4DI I was talking to Robert and he reckoned the way to get perfect prints was to print with no adhesive on the bed and whack the printing bed temperature up to 70 degrees (which is actually rather hot for my tastes).

Anyhoo, I tried it today and it works a treat. The PLA sticks to the clean glass surface and then when everything cools down the prints just pop off the print bed with no problems. And each print has a lovely glassy smooth finish on the bottom.

I'm kind of annoyed that I didn't try this earlier. Why would I have a heated bed on the printer if I didn't actually make it properly warm? Anyhoo, I'm now turning out lovely tags. They'll be on sale next week.

3D Printed Red Nose Day Tags

Tags Ready for printing

Tags Ready for printing

Red Nose Day is a UK charitable appeal. I do Lectures in Rhyme for it and all kinds of silly fun stuff. If you want to sponsor me for the next one you can do so here:

Last time we had a Red Nose Day I had some RFID tags that I used as the basis of a raffle. The holder of the winning tag won a rather nice Gadgeteer kit.

This year I thought I'd try something different. I thought I'd 3D print some tags and sell those instead. Each tag is completely unique thanks to a Python program that I've written that creates a combination of square and round layers of different sizes on the top of each one. Above you can see how this works. Each tag has five layers on top, of which two are square, the rest round. The square layers are rotated a random amount too so that there is plenty of variation.

I'm going to print only one of each tag design, except for the winners, where I'll print a "golden" tag as well.  We'll draw out the golden tag at the lecture on Friday 13th and find the winner. 

Printed tags. I'm going to do lots of different colours.

Printed tags. I'm going to do lots of different colours.

I'm quite intrigued by the idea of using software to produce 3D printed objects which are unique. This lets me explore the field in a good cause. 

The tags will go on sale later this week at a two pounds each. You can do what you like with them, they'll come with a keyring attachment, but you could use them as unique earrings if you were so inclined. And the more you buy, the more chance you have of winning our top secret big prize.

Note: Sharp eyed readers might have noticed that some of the red tags above have more than two square layers. These are test ones that I produced while tweaking the code. 

3D Selfies to Celebrate Kinect V2 Release

To celebrate the release of Version 2.0 of the Kinect for Windows 2 SDK I printed a couple of selfies of me using my Carbonizer program and changing the filament half way through the print to get a dual colour effect. I'm quite pleased how they came out. I wish I'd kept my head still during the scan so that my features show up a bit better. Then again....

With the latest release of the software we can now put Kinect for Windows apps in Microsoft Store. I might see about a formal release of the Carbonizer program. Microsoft have also announced a new $50 adapter that lets you use your Xbox Kinect with your PC, which is nice. You can find out more here