The Long Tall Model

That Kept Falling Over.

Because of this: (https://study.com/academy/lesson/law-of-the-lever-definition-formula-examples.html)

Someone on a forum I'm in had issues with a tall skinny item of which every attempt to print kept detaching when it got to a certain height and they thought their printer had a fault and were looking into stabilising the Z-axis lead screw and all sorts.

Hoping their issues have now been sorted out by the conversation we had.

The issue's a well known one - and the standard solution is to print it with a brim, or in extreme circumstances with a raft. And it's to do with levers, as the beginning link indicates. 

Quick example: 
I'm printing models of various antenna towers. The models are a pyramid shaped tower, a square section tower, and a square tube tower such as is used for cellphone antennas. Cases A, B, and C:

All the maths you need are the formula for levers (F1 x L1 = F2 x L2) and for surface area (L x W) of the base of each print. 

For this exercise let's assume that the models will include all the ground it's standing on and all are 15cm tall. 

I'll use lengths of  4cm, 2cm, and 1cm for L2 in cases A, B, and C respectively. L1 will be 15cm in every case, and we'll work on the forces once we have the maths.

So the surface area under each print comes to 16 square cm for case A, 4 square cm for case B, and 1 square cm  for case C. If we assume that it take about 5g of force to separate a model off the bed for each square cm that makes the breakaway force 80g for case A, 20g for Case B, and 5gm for case C.

So the F2 x L2 portion of the equations will be 80x4=320 for A, 16x2=32 for B, and 5x1=5 for C.

That means that at that point 15cm up, it would take 21g of sideways force to rotate the base off the print surface in case A, 2g in case B, and a force of just 0.3g in the case of the skinny model C.

Conclusion

A brim is attached to the bottom of the model and increases the surface area in contact with the print surface, increases the length of L2 which adjusts the lever ratio and makes it harder for the print head to pull the model over. As you could see, a small increase in the base makes a great deal of difference in the printability of a model. 

Try it - print a cylinder of 0.5cm diameter and 200cm tall (in vase mode if you like, for speed) and see how tall you can print it before it gets pulled over. Now add a brim of 0.5cm width all around and try again. I bet you won't get more than 5cm in the first case and probably a full print in the second.

Footer

As always, please share this article and my others like it, go to my News Stand to see all my other posts and share links to the News Stand and any articles you found interesting, and if you can, donate here or here and find out here why it's important. Or subscribe to my once a week newsletter and stay in the loop.

Tips: Glass Print Surfaces

How To Stick The Print

Not sure if I've mentioned this before but good service begets good custom. That's how my Ender3 Pro ended up with a Creality glass print surface. 

Backtrack:

The year was - umm, 2020 (I think! Damn COVID for timewarping me) and after a year of saving pennies (or was it 2021? Argh!) and a lucky break where two companies each had a sale event and the combined total was under AUD$240 delivered to my door within 4 days, so (early 2021 for sure!) it was definitely time to buy. 

I had one of the batch with a warped print bed and a magnetic flexible print surface, and after setting a straight-edge across the bed and taking a few pictures, I contacted Creality support and while they did try all the usual ways to get out of it, after a fortnight of back and forth, they sent me a new heat bed and magnetic flex surface. 

Back on track:

And because they actually also asked me if my control panel was beeping (it was) and sent a new one at the same time, I became their best evangelist and sold three more Ender3's of various flavours for them just through chatting to a few of my friends online. 

And I also bought a glass build surface from them soon afterwards. Just because. And oh did I have a helluva time with it. Nothing wanted to stick on the corundum (??? something like that ???) side, in desperation I turned it over and used glue stick to print, which worked for a week or so when I needed to remove the old glue buildup.

Now to two confessions. One, I used bulldog clips to hold the surface down, and they are springy, also (as I'll get to in a few minutes) they get in the way a fair bit. Second confession is that I take the whole glass plate off each time and wash it in the kitchen sink with a spot of detergent. Hey - I do the cooking, my kitchen. . . 

So then I thought maybe I should try the corund- the coated side again, and after a quick level, it worked! Here's a video from Lost In Tech that I guess I should have known about, that says essentially that - wash the build surface with water. (BTW if you like that channel maybe subscribe and make sure you give them some Like love too.)

Those bulldog clips:

They are springy. That means that if you remove the glass build surface and put it back, sometimes a speck of plastic can get under, or it can be pressed down a bit too much at one corner, or any of those other random issues that mean re-levelling the bed every time a clean is needed or a part has to be removed. 

They are also surprisingly awkward and get in the way. This meant that on a print that went close to the limits of the bed size, I watched the sharp rolled edge of the clip slice the silicon sock off my hot end and - that was that for three weeks until I could get a new one, because the prints looked awful and had issues.

Oh, the time window? 'Straya, maate! Getting anything like that in Australia was possible but remember I'm on a pension and to order a pack of socks from China and pay delivery was still cheaper than buying one sock locally. Essentially, our Australia Post postal service charges as much or more for a delivery from a few hundred kilometres away than I got charged by a company in Shenzen city. And their five silicon socks was only marginally more expensive than one from a company that shall remain nameless  downunder here.

So I got me some 7mm stainless steel flat clips made for the job, and they are actually very good and I thoroughly recommend them. Also, auto leveling, I intend to do that too, I have a probe and just need to get clicking with the firmware, for now I just use the paper test to adjust the intital layer height and (rarely) adjust by 1/16th of a turn while the skirt is printing. 

Footer

As always, please share this article and my others like it, go to my News Stand to see all my other posts and share links to the News Stand and any articles you found interesting, and if you can, donate here or here and find out here why it's important. Or subscribe to my once a week newsletter and stay in the loop. 

 

3D Print Less Wastefully

Use Your Printer More Mindfully

You know how you bought a 3D printer to do great things? Well, here we are, you and I, and at least one of us has been through a few kilos of filament and is still feeling okay about it. (Clue: It's me... 😸) 

Why? Read: Recycle Guide. There's half a dozen things in the article that you can do to manage your printer and keep your plastic waste footprint down. Apparently we might be eco-vandals for printing with plastic, and should be ashamed. Or something. And I like All3DP, they were one of my prime sources for info and still one of my go-to's - but this article almost made me not feel okay about my FFF hobby. . .

But don't let the article snow you - the amount of waste filament of the "...large 3D printing community..." isn't as much as you'd believe. Coupled to this is that members of that "large 3D printing community" are already a bit strict about their wastage, i.e. they mind their expenses. 

But right away the very next tip is to reduce supports, adhesion, and infill. I'm going to say it - don't do that. By taking away those supporting parts, you're effectively chucking 12 years' of combined Maker experience down the dunny, your parts may fail to adhere, fail to print properly, and/or end up too fragile for purpose, meaning instead of putting a few bits of support and adhesion print into your FAILS bin, you'll be putting the whole model and starting again.

You know the feeling when a 16hr print comes unstuck in the last hour because it got tall enough for the leverage of the sticky hot nozzle to break the base of the model off the bed? It's a totally AAARRGGGHHH!!! feeling when it happens. And then a few hundred grams of insufficiently supported plastic ends up having to be thrown out and the object reprinted. I prefer to save my sanity. When a part is going to be skinny and tall, print it with a raft or brim, go on - devil take it! - use that extra half a gram of filament!

If you're (as the article also says you should) recycling all your waste prints (and you should be doing this for sure) what's your strategy? Does everything go in the FAILS bin together? What sort of strategy is that, other than a really bad one? I have a big bin for PLA because I find PLA does a good job for my range of  prints. That picture is my "big" bin of supports, adhesion plastic, and odds and ends of filament from nearly two years and countless spools of hobbyist level printing.

This is my filament ends and support
waste - from two years of printing.

There are about twelve re-used old plastic vegetable bags in there, each with just one specific colour of filament, and these contain all my 'wasteful' support and adhesion waste. Keeping it sorted by colour means that I can recycle my filament in a colour other than "Depressing Grey Drab" when I get to do it. And I know it's all PLA in that particular bucket.

I also have a single bag for PETG because I actually have a single spool of PETG in a  chic shade of Depressing Grey Drab that I've used for two models because they needed to survive a bit more heat than PLA can handle. I have a single 4litre tub with failed PLA prints, drafts, and test pieces, stuff that turned out not to be wanted. It's easy enough to sort into colours too. 

I can't stress enough how much more useful your old plastic is if you keep it sorted by type AND colour - and being how I also try to recycle all our household plastic, that's paid off with all the HDPE, LDPE, and PP that I've got sitting outside in old buckets and bags and so forth. I guess if you're a regular reader you'd have heard me mention it. 

Making filament at home from printer waste can be done and is probably a good idea - if you can afford the cost of those machines, and can live with the realisation that you'll maybe recycle five spools of filament's worth of scrap over the entire lifetime of printing that you'll do. For that, you'll have consumed several stepper motors, cogs, gears, power supplies, control boards, and a whole heap of your time. 

I can't justify that as a hobbyist. If I was a commercial printer making hundreds of kilos of parts every year, it *might* make sense if I have a lot of support waste. I'm not going to say "failed prints" because if you have a lot of failed prints then maybe commercial 3D printing isn't for you . . . 

But - if I can after five or six years of printing send my waste to a filament maker, and they can recycle it easily into coloured filament because I've sorted it for them, then I'm down with that. They'll have the machinery to do it already, me sorting it for them will mean they can use it to make nicely coloured new filament, and everyone benefits.

If you balked at the "nicely coloured new filament" bit above, consider this: part of the problem with plastic is that it LASTS such a long time without degrading. And melting a plastic and re-forming it at the right temperature won't degrade it, it'll be as good as virgin plastic. That's what plastic is infamous for after all . . .

Sidebar: You know how soft drink manufacturers won't take back their huge mountains of plastic empties? It's NOT because the new bottles made from the old PET will somehow be crappier than a new one. It's because it's "too expensive" for them to add the steps of shredding and washing the old bottles. Yup - these companies are watching the world being choked poisoned by their products because they're too tight-fisted to deal with their waste themselves. 

And the only reason they keep doing that is because we - you and I and everyone else - keep buying their product and not insisting that it be put in glass or in a returnable recycled container. 

An Exception To The "Don't Recycle At Home For 3D Printing" idea:

One of the things I'm working on (as mentioned a few paragraphs back) is recycling my household's plastic waste (and a lot more waste streams, once I can afford to make / buy the gear to do so) and currently all I can do it use it in flat sheets or in ironed-onto-cloth form. But if I can afford to make a shredder and quick and dirty extruder, I can make pellets out of the plastic waste, and those pellets can be used in a dozen ways, including as filament and in pellet form to 3D print. That's the only way I could justify the monetary and ecological cost of a filament making setup, and only then it would make sense to also recycle my old PLA waste, seeing I'd have the gear on hand. 

There's also a few 3D printer hot end/extruder setups now that use pelleted plastics, and can print my PLA if I make it into pellet form and save the step of extruding filament. (Read the last part of the article about how filament needs to be cooled and why home setups can't compete with the 10 - 30 metre cooling path that a filament factory can spread out across. All not necessary if you use pelleted plastic stock.)

Conclusion:

Don't stress too much about your plastic footprint. Instead,. make sure you have a good recovery, storage, and send-to-recycle plan for your scrap plastic. Don't take too many reckless shortcuts with the actual prints themselves, try not to print too many single use items. (I print the odd trinket for the house such as a small Nefertiti bust or a few wall butterflies, but they're part of the decor and will stay in use for 5 - 10 years. Other than that I try and keep my prints utilitarian. And I try to nail dimensions with as few iterations as possible, and have even been known to print only two layers then aborting if I needed to check a design for fit,) 

Most of all, enjoy your models and keep pushing designs - of both printers and products. 

Footer

As always, please share this article and my others like it, go to my News Stand to see all my other posts and share links to the News Stand and any articles you found interesting, and if you can, donate here or here or here. Or subscribe to my once a week newsletter.

Rite Of Passage

Making Stuff

ptec3d 8th

So as you know I don't often get a chance to actually buy things. Pension sucks, scrimping sucks. I do surveys for the $20 threshold every couple of dozen weeks, and that's my mad money. Well, about two months ago I "invested" my twenty in Lotto because I felt lucky. And it paid back just under a hundred bucks, so I was able to splurge (by my standards anyway) and sent away. 

So I Crossed Some Sort Of Maker Rubicon

It seems to me that every maker that works with 3D and CNC and FFF and that, has some aluminium extrusions. Check.

Extrused.

I also note that they often use 6mm T2.2 timing belt. Check.

Belt, check

And powered and idler pulleys for the belt. 

 

Oh yeah - and that's a check too.

Now For The "Why"

It's like I knew (Oh hang on - yeah - I did know) that these things were arriving. I've been wanting to build a bit of a CNC machine on the (VERY) cheap. I have an old Makita plunge router that's still got good bearings so the spindle was taken care of. Motion components are a bit different. But I also had the ill luck to buy a Canon MG3660 inkjet. That died in under a year after consuming less than one new set of cartridges. The warranty replacement also died in less than one cardridge change, and the third one has now lasted two years and two changes of cartridges. (Fingers crossed!)

They didn't want the old printers back. I think they probably have a huge stack of returns out the back or something. No, I'm not saying what the company was. But it did mean I had a supply of reasonably smooth linear motion components, and a pair of everything, at that. If you're not thinking "Oooh! X-Y motion components!" by this stage stop reading... hehehe just kidding, read on we'll make a Maker of you yet.

 

And so I printed an adaptor to replace the 12V DC brushed motor and replace it with a NEMA17, and (hopefully) a pair of pulleys and some ingenuity would let me make a stable axis in one direction or the other. Or both, preferably both. But it became obvious that the plastic slider alone wouldn't be stable enough by itself. Lucky I'd ordered those parts including some 2020 extrusion, and have a heap of rollers, and a 3D printer.  

And that's where the project currently sits, because I have to do other boring things in between, like blog posts and setting up a Confluence space for a side project and you know, cooking and laundry and boring stuff.

This Is The End

... of this article. But it's nowhere near the end for me. It sometimes takes several days to find a topic to write about, properly research it, and then write and schedule it, unlike this article where it took me months to get everything together. Hehehehe. I don't have any assistance and I don't have the kind of income that allows me to use a scheduling service like established writers can. I also spend some of my limited pension on keeping servers and domain names going, more on parts for the R&D I buy for      making machines for recycling waste. You can help me by sharing this article or the link to the newsletter I put out, or more directly by making a Paypal donation here. Failing that you can also go to my Ko-Fi page and set up a monthly donation. (It's like Patreon without all the bullsh*t.) Everything you can do, will help me keep going.