Lessons in 3D Printing: Blobs, Warping, Gaps, Ugly Overhangs, and other disasters with gravity

What do you do after you've let the printer go on printing for several hours but all you have left to show for your efforts is a big fat deformed blob of PLA? Well, after incorporating a 3D printing component to the 3D module I was teaching, I found myself dealing with many different cases of 3D printing disasters which I'll document here as a cautionary tale of the futility of logic and planning in the face of the freak accidents and an uncaring machine...

1. Blob around Extruder

What is it? Item comes off the print bed midway, sticks to the nozzle, and envelopes the entire extruder as a blob of goo which once hardens may make it impossible to remove from your printer.

How to fix? Watch your prints from start to finish (often this is impossible and impractical to do) or try to set up an IP webcam to catch instances where this is happening.

2. Warping

What is it? Warping is when you have a large part to print and the first layer which originally adhered so well begins to warp at one corner because of uneven cooling.

How to fix? The obvious fixes for this is to use a heated bed (check), use a heated enclosure (check) and print with a good brim or raft (check). Unfortunately even my rafts still continued to warp, so the main solution I used to fix this is to avoid the edges and to avoid overcrowding the print bed. I say solution but really it was just a temporary coping mechanism to try to get on with printing despite occasional warping.

3. Gap between parts

What is it? This is where someone has designed a part with an error and failed to check if the slicing is alright, resulting in this mess.

How to fix? Check and double check the design of all parts before printing! Look through every single layer if you have to to ensure that the thread continues and doesn't just stop for a few layers.

4. Insufficient supports

What is it? Many a time I would see a file that did not seem to have sufficient support to keep the object from falling over. But since I wanted to make a teaching point of this, I let the item go to print so we could all experience the failure together. Now that I have observed several hundreds hours of prints, I find that I am pretty accurate at eyeballing a print and determining where a print lacks the supports for it to complete without falling over.

How to fix? ADD MAXIMUM SUPPORT. Don't just do what you think is the minimum, because that is almost certain to end in tears. Add the maximum amount of support needed if possible and accept the fact that the only way to get some objects printed is to allow it to take the longest possible time to print (with all the additional support)

5. Ugly Overhang

What is it? This is where you knew the printer would make a squiggly mess of the overhang yet you let it go on printing.

How to fix? Like the previous support issue, you just have to add more supports than you think you need. Or slice the item into half and lay flat the two halves to print.

6. Flipped Normals

What is it? If your 3D model has errors or flipped normals in any portion of itself, it may be translated into a weird shell of itself if you forcibly slice it into gcode.

How to fix? FIX YOUR MODELS COMPLETELY BEFORE SLICING THEM.

Bukit Timah Nature Reserve and Singapore Quarry

It has occured to me that I really should resume my documentation of various walks since some of my drafts are almost a year old now... SO I CAN KEEP IT CURRENT AGAIN IN THIS BLOG!!! Let me kick things off with a documentation of some of our weekend walks in Singapore...

Bukit Timah Hill Summit and Singapore Quarry

A few weekends ago we decided to go on a walk through the Bukit Timah Nature Reserve and began our journey on Upper Bukit Timah Road, near to Beauty World and Bukit Timah Shopping Centre, singularly populated by maid agencies and tuition centres. On the road itself at the end of the mall, there was this little "gratitude" altar made out of this extruded clay material. We were going to go through Hindhede Road and walk to the summit of Bukit Timah Hill...



....and then maybe because its just Singapore being small, but it seemed as if we got to the summit almost immediately after a little walking uphill and then everything from there was downhill (literally). At 163.63m high above sea level, this is Singapore's highest hill (and largest primary forest, from which many botanical collections have been derived from). Deforested by the encroaching gambier and pepper plantations at its foothills, the forest was identified by the colonial government as an area to be conserved (although this only took effect after a significant portion of the forest was lost) and there were some reforestation works (largely involving economically useful trees though).

But is it so tiny? To be fair since we are talking of hills in cities, I looked it up for comparison: Hampstead Heath's highest point is 134m, Crystal Palace's Sydenham Hill is 112m, Muswell Hill is 105m, Highgate Hill is 100m. I suppose that most do not experience the hills in a direct fashion as our houses are not built on hills like these, whereas it is common to have houses on a steep hill in the UK. (I have a distinct memory of watching a television advert for a car on Singapore telly when I was young and snorting at the advert which was selling the fact that the vehicle could cruise up a 40 deg hill with a full load and no problem but in my limited experience when I was a child I never saw any hills matching that description in Singapore so it was a moot selling point to me!)



Lovely seat in the jungle - that is if you dont mind sitting still so that the mosquitos can eat you better.





There were many forest paths but we did not see any unusual animals or monkeys. (Apparently I had oversold the prospect of sighting monkeys a wee bit too much to George)



Weird black goo on a tree.



The cliff's edge





A little stream along the way





A prickly Rambutan, or an Allamanda's fruit?







Long stairs down...





Leafy Ferns - Bukit Timah is known for its many ferns and there's supposed to be some "Fern Valley" in it but I don't know if this was THE fern valley.



By this point we were back in Civilisation and along the roads, but since we were pretty close to the three granite quarries, we walked to the nearest one to us, which was the (somewhat unimaginatively named) Singapore Quarry, one of the granite quarry which have since been turned into a beauty spot where school children have picnics and people come to take scenic yoga instagram pics...







Singapore Quarry
This walk took less time that I thought it would, but the heat and moisture does get in the way of things, giving the impression of a monumental exertion over what is really just a modest hill.

Piccadilly in Seletar: Down the dead end road

If we had to give our walks a ranking of enjoyability, this would not be one of them. I say this because whilst we were on this walk, George actually told me that outright. "Debbie, if we were to give our walks a ranking of enjoyability, this would be one of the worst ones so far, where is the nearest MRT, I'd like to go home now please".



We began this walk at the Oval at Seletar Aerospace park, which had an airplane themed playground not so far away from the actual seletar airport itself, where you can watch small private/chartered planes taking off and landing. It started off quite promisingly...

Seletar Airport was the home of a Royal Air Force station in Singapore (1928-1971). During WWII it was one of the sites targeted with carpet bombing. For some time it was the first international airport in Singapore (before Kallang Airport) and after the British pulled out of Singapore it was handed over to RSAF. There had been proposals to lengthen the runway so as to be able to receive the 737 used by a lot of budget airlines but those plans were canned and instead the new passenger terminal being built in Seletar will be mainly for those using smaller and slower planes.







We got to Soek Seng Bicycle Cafe which I suppose has a lovely view and could be something to look forward to at the end of a long bicycle ride, but for pedestrians on the long stroll I have to say there are not so many redeeming factors. This area seems designed for cars and planes, and not so much for people to walk on foot to explore.













At the end of a very long meander down lots of old Seletar camp buildings (with nearly no other humans besides workers in a nearby construction site and some cyclists speeding past), we ended up at a dead end that overlooked the waters with absolutely no way for us to cross it.



Since it was home to the RAF base there are remnants of black and white houses which were used to house the British RAF servicemen/women and their families - and many road named after places in the UK:



Behold as we walk down the bustling busy surroundings of Edgware Road



Let's do the lambeth walk down Lambeth Walk



What about a hugely exciting walk down the lively Oxford Street


As Oscar Wilde did write in Dorian Gray: "As I lounged in the Park, or strolled down Piccadilly, I used to look at everyone who passed me, and wonder, with mad curiosity, what sort of lives they led. some of them fascinated me. Others filled me with terror." The terror of a walk down the nether regions of Seletar to a dead end construction site - where the adjacent waterways smelled strongly like human sewage and the roads were given names like Piccadilly, Maida Vale, Regent St, Baker St, Park Lane, St Martin Lane, Battersea....



Welcome to Piccadilly in Seletar, Singapore

A Quick Guide to Samplr

This is the only time in years when it has seemed worth buying an iPad again. The current iPad 2017 9.7-inch is quite reasonably priced in its class (32GB - S$498 / S$468 Education) and Apple still has some of the best apps (and ARKit!). And for the most part I hadn't needed a tablet sized device for work until now. The problem with with smartphones or even phablets (such as Samsung's note phones) is that when you do get long work emails that you urgently need to reply to, then even the on-screen keyboard on the large phone screen still feels like a constraint; one can't really draft or write long documents on a phone keyboard and is reduced to nervously turning the phone on and off nonstop to stare at the email that you can't properly reply to. But a decent sized tablet paired with a bluetooth keyboard pretty much solves this conundrum; the 9.7inch ipad is powerful enough as a lightweight laptop-replacement where administrative paperwork is concerned.

But the iPad's strengths are more than just clearing emails and drafting google docs/sheets with ease - it also excels at many other things such as MAKING MUSIC. Two essential music apps for the iPad have got to be the combo of Samplr (S$ 14.98) and Audioshare (S$ 5.98).

Samplr is a brilliant gesture based audio sampler with many rich effects and modes which can be used together with Audioshare, an audio document manager which transfers audio files between apps and between the device and computer. For some time I have just been stabbing at it without really knowing what I am doing, but this weekend I sat down to go through the help docs and a few tutorials online; I didn't immediately find a guide sheet so I made my own for Samplr here:



Samplr guide (Click to see large version)
One thing I've noticed as someone who purchases digital products items from both UK and SG app stores (with both UK debit card and SG debit card) is that the UK prices are a total rip off because haven't fallen in line with the pound which has devalued considerably since, so I always buy in SGD from the digital SG stores these days. This also applies to Steam where the SG pricing for digital products and games is far lower than the UK pricing for games. I wanted to purchase a game for George's steam account recently but because I was purchasing in SGD it would not allow me to 'gift' it to a UK account.

There are also tracker sites such as steamprices.com which you can use to compare the inequalities of purchasing a digital product in a specific currency....



Steamprices.com - where you can find out how much you've been stiffed...