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Comment by msds | Hacker News Reader

I really don't understand the appeal of this sort of machine. I have a pretty big (300x300x300mm) and very fast printer, and large prints are still annoyingly slow and expensive. I can't ever imagine FDM printing (especially with a small, filament-fed hotend) being an appropriate way to make "arbitrarily long" objects. Other people have scaled the platform I have up to 500mm and 700mm, and get great results on genuinely large objects too, not just on long things.

Furthermore, the volume production stuff is just silly. If I'm printing a bunch of small objects, I'd rather fill a build tray with them, and then swap it out every 8 hours when it's done. The belt release stuff really seems to have reliability issues. Or, just use an appropriate manufacturing technique for high volumes...

Maybe I'm just a curmudgeon with bad memories of belt build surfaces from a Thing-O-Matic.

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I liked the example from Naomi Wu's twitter, that used it as an assembly line to print many identical pieces (or each slightly different) and drop them into a bin.

https://twitter.com/RealSexyCyborg/status/130143777389991936...

I also use my printer as the first step to a lost wax casting technique. A much longer print volume might make some steps easier, not having to connect multiple (or maybe just not as many in some cases) prints together before encasing in plaster. Sure I could just use a larger volume printer, but this is an interesting optimization to me that might fit in my shop.

Can’t you do that with a regular printer and the last line use the print head with a shovel thing attachment to push it off the bed at the end?

Maybe, though you risk breaking the print head if the print is stuck to the print surface.

I've done this before where we were printing thousands of small objects for a small scale production build. I attached a kicker plate to the print head and modified the gcode to pop it off into a chute before printing the next one. This only really worked because the print was small with little surface area adhering to the print bed.

In all honesty injection molding makes far more sense once you get into high enough numbers assuming the geometry is amenable to that.

Long objects I think are the main draw in that this is one of the very few ways to make them at home. Whether it will work or not isn’t clear but it certainly is one of the cool things.

The continuous production is neat in that you might not want to print the same thing over and over. Say you are printing miniatures that you sell on Etsy. Order comes in, goes straight into the printer queue and all you have to do is toss it into a box and ship it when it’s done. Of course if you are producing thousands of identical objects then something like injection molding will be better. But if you are producing thousands of not quite identical objects, this would be a fantastic system.

The long objects idea neglects basic physics - unless the part hanging off the side is very light, at certain point it is going to drop down and peel the other side from the belt, ruining the print.

So in practice such machine will be limited to printing objects with maybe 2x the length of the belt max before the belt deformation and objects peeling off become a problem.

You really wouldn't want to do continuous production like this - the printing surface needs to be cleaned too, glue or whatever you are using for adhesion re-applied, otherwise the adhesion and finish will suck over time, causing problems. How are you going to do it on a moving belt while the machine is running? Sure, it can be solved but the Creality machine doesn't have any provisions for it.

And if you are producing thousands of not quite identical objects, buy three or four printers instead - the production will be much faster and more reliable than this belt nonsense, especially today when a printer can be had for less than $300 ...

Just put a roller stand or two at the end adjusted to the right height.

> The long objects idea neglects basic physics - unless the part hanging off the side is very light, at certain point it is going to drop down and peel the other side from the belt, ruining the print.

Well this man made the unfortunate mistake of printing an 8ft long object twice and merged the resulting halves into one object and thereby violated janoc's laws of physics.

https://youtu.be/wm9H_ApiidM

Hello fellow 3D print curmudgeon,

The Makerbot Automated Build Platform was terrible in many ways so an eternity ago I forked ReplicatorG and got it printing continuously from a queue.

Once I did that I really appreciated being able to leave my printer running all day and have it produce bins full of parts. I especially appreciated being able to add prints to the queue while iterating on my CAD designs.

So, shameless plug: Inspired by that experience with the Makerbot I've been writing an entirely new print conveyor-ready print queue for the raspberry pi. Coming this fall at https://tegapp.io/

As someone who is quite deep into this as hobby I have to agree. "endless" printing is a niche feature that would barely see any use. The reasons are:

1. Just look around you: Where do you see bigger than 300mm^3 (around the maximum size of common FDM printers) plastic objects? Barely any. Larger single-piece objects (or parts of them) are made from metal, wood etc.

2. To make things worse FDM parts are weaker than injection molded ones, your big parts will be very brittle.

3. FDM printing is inherently an unreliable process. There are lots of moving parts (the simplest FDM printer needs 4 motors, lots of belts, idlers, gears etc) and very tight tolerances (e.g. the print needs to begin 0.08-0.12mm above the printing plate; the whole priting plate needs to be very level and parallell to the printhead.). This is achievable at surprisingly low cost today (an entry level Creality printer is <200$), but it needs constant maintenance - meaning you need to adjust something around every 20-50 print hours. (I guess industry grade machines are better, but Creality is aiming for the hobbyist market.). So in practice your "endless" print will likely go wrong after a day or so making it useless.

4. If they dont go wrong slight misconfiguration or misalignment causes your prints to be ugly/faulty. And even a perfectly tuned FDM printer cannot reach the precision of an injection molded part. Just to get a picture heres a link that shows how many things can go wrong: https://www.simplify3d.com/support/print-quality-troubleshoo...

I am starting to think that FDM based printing is a dead end in the history of 3D printing (mainly because of reason #3). Likely the future is resin - a simple LCD resin printer has 1 moving part. But they need to solve the issue that most resins are nasty, toxic materials that you dont want to have around in your home.

I like resin but doesn’t that limit your choices of materials? And isn’t there a lot of post processing?

An increasing library of materials is becoming available for SLA, e.g. I've used those with properties resembling clear acrylic, silicon, rubber, ABS-ish, bio-compatibility for dental, "nano-dispersions" for tinting and even some exotics infused with glass powder or with high temperature-resistance (HDT of 238°C @ 0.45 MPa). But FDM still offers more variety (e.g. carbon fiber infused filaments).

There's post-processing if you do prints that require supports (overhangs, etc). I've gotten good at designing within the constraints of the process to eliminate that as much as possible, but yes, it's still a pain.

A typical advantage of SLA over FDM or SLS is a smoother surface finish. But I think the industry will ultimately land on a material jetting design (akin to an inkjet) that can dispense multiple types of polymers and dissolvable supporting material. The NexD1 had promised to be the first consumer-grade printer to do this but it was a scam.

I print a lot of miniatures which require tons of supports, but the support process most people in my space use result in supports that are incredibly easy to remove - it got to a point for me where I enjoyed removing supports that I was printing too much. Sort of like when we'd put Elmer's glue on our hands just to pull it off after it dried back in school. :)

Post (or pre) support removal is an isopropyl or acetone (or other agent) bath to remove any liquid surface resin and then a final UV curing.

I use an Anycubic curing station so that definitely speeds things up. To process a full build plate from my EPAX X10 it takes upwards of five minutes of my time [in terms of attention] (plus six minutes in the alcohol bath and six minutes in the UV cure chamber, which are both unattended processes).

Interesting. How much faster is the print time vs fdm?

It's much slower than FDM (at least in my experience using a formlabs printer).

It really depends. an LCD resin printer prints a single layer at once, but it prints much smaller layers than an FDM printer (resulting in better quality). So for something small like a minifigure FDM will be faster, but for something big (especially if it has lots of small features) resin is faster usually. And resin prints are always more detailed.

most resins are nasty, toxic materials that you dont want to have around in your home

Got a source for that?

I've been using Formlabs resins since they did their SLA Kickstarter ~6 years ago. Never seen any toxicity warnings in their MSDS. Know lots of other people who use them, including a couple who ignore all the guidelines and get their hands covered in the stuff. The worst I've heard of is something like a skin allergy reaction after prolonged, chronic contact. The company themselves have dozens of employees printing with these things in regular office environments and their homes, and I imagine would get a nasty lawsuit if it turns they've been subjecting their staff to toxic conditions. Also know loads of people who run with third party resins (e.g. Peopoly is popular at the moment).

Eye irritant and skin irritant. The only toxicity one mentioned is reproductive toxicity; it causes reduced fertility and shrinking of the testes:

https://archive-media.formlabs.com/upload/Clear__Resin_SDS_E...

> Repr. 2, H361f (Fertility, causing [1] atrophy of the testes)

That's for uncured resin, which you shouldn't touch anyway. I think protocol calls for using gloves when handling this stuff.

Do you happen to know if that fertility issue is only for clear resin, or all resins they offer?

Frankly somewhat surprised to learn this. I think I've seen them push clear resin for microfluidic applications where you would have biological samples, which would indicate low or no toxicity.

> That's for uncured resin, which you shouldn't touch anyway. I think protocol calls for using gloves when handling this stuff.

This is the issue with hobbyist use. Of course there are protocols to handle it safely, but such things make it inappropriate for the average joe.

I agree with you it's not for the "average joe".

I.e. yes you need to be really careful not to touch the uncured resin, cleaning up is a bitch, and you need really good ventilation when you're developing with isopropyl alcohol.

But for folks who do manage to somehow get a room dedicated to this craft, of a hobbyist hackerspace with a dedicated spaced, it's probably fine. And, I think arriving to the point of being able to make a good print (modeling, slicing, etc.) is a good enough filter -- folks who can do that will and should understand you need to wear gloves when operating this thing. And I do believe if you get a printer it comes with a few gloves so that is made pretty clear.

The resin itself isn't a huge problem. It's that it will enter and cure inside your body. This causes an allergic reaction that will grow stronger over time until it becomes unbearable.

> 1. Just look around you: Where do...

I mean, I actually see quite a few, but none of them are things that I would ever bother printing since I can just pop around to the store and buy a new garbage can etc...

> 3. FDM printing is inherently an unreliable process

Yeah, I have a well-tuned and reliable machine and it's not really cut out for long stretches of lights-out operation. Worse, most failures are at the bed/plastic interfaces. If you're printing conventionally, that's great because things fail early - but this belt process manages to stretch out the process of making that interface throughout the entire print.

> FDM based printing is a dead end in the history of 3D printing

I don't think so. It's a mature technology, and is already quite useful. It's not going to radically improve in terms of geometric accuracy/feature size, but materials are constantly improving and I'm excited for stuff like ASMBL, tool changing printers, and more multi-material/multi-process integration in general. I don't really see 3DP ever getting to "magical replicator" levels, so if FDM is a dead end, it has found a nice little cul-de-sac in the same neighborhood as the eventual end-game printing process.

> Just look around you: Where do you see bigger than 300mm^3 (around the maximum size of common FDM printers) plastic objects? Barely any.

I wonder if that's a effect or a cause though?

There were barely any cars on the road in 1900. There were very few super computers in people's pockets in 2000.

I know literally 3 or 4 people who'd jump at the chance to use one of these to print model glider wings (or at least moulds for them). There might be several hundred or even _thousand_ potential customers for that around the world ;-)

I can't think for any actual real world useful use cases for this, but I'm somewhat hesitant to use the "but nobody has the kind of thing this makes possible now" argument against them... I am highly aware of my lack of imagination and my innate ability to go "Well, yeah, that's obvious!" after someone with a way better imagination than me does something creative with new tech...

>"endless" printing is a niche feature that would barely see any use.

3D Printing pieces for large scale unique art projects (some people make a business out of this), producing a steady stream of parts for a small business, printing very long pieces. That's just ideas I had in the last 15 seconds since I read your comment.

>1. Just look around you: Where do you see bigger than 300mm^3 (around the maximum size of common FDM printers) plastic objects? Barely any. Larger single-piece objects (or parts of them) are made from metal, wood etc.

The guy (NAK3DDesigns) who created the design the Creality Ender 30 is based on is exclusively printing large objects like guns and swords as two halves that he glues together. Pretty much most of them are longer than 1m. If I had such a printer I probably wouldn't hesitate printing 50cm long parts.

>2. To make things worse FDM parts are weaker than injection molded ones, your big parts will be very brittle.

Not everyone can afford to spend a few thousand dollars to make single unit parts. Especially when you exceed the size of most injection molding machines you would have to either use multiple molds or one gigantic one which will cost more than $10000 for something you only make once.

>3. FDM printing is inherently an unreliable process. There are lots of moving parts (the simplest FDM printer needs 4 motors, lots of belts, idlers, gears etc) and very tight tolerances (e.g. the print needs to begin 0.08-0.12mm above the printing plate; the whole priting plate needs to be very level and parallell to the printhead.). This is achievable at surprisingly low cost today (an entry level Creality printer is <200$)

The reason why 3d printing is low cost is that rigidity requirements are low. On a 3d printer you don't even need a ball screw or linear rails. Just a belt with a crappy tightening mechanism and some plastic rollers on an aluminum profile are enough. There are no cutting forces in a 3d printer and the print head weighs laughably little so you can get away with small stepper motors.

>I am starting to think that FDM based printing is a dead end in the history of 3D printing (mainly because of reason #3). Likely the future is resin - a simple LCD resin printer has 1 moving part. But they need to solve the issue that most resins are nasty, toxic materials that you dont want to have around in your home.

Funny that you say this but I personally don't want an SLA printer precisely because of the nasty side effect of photosensitive resin. One day you'll become allergic and that's the end of your hobby. FDM printing is safe and mechanical reliability is just a property of the specific printer, not a property of the process itself.

> Furthermore, the volume production stuff is just silly. If I'm printing a bunch of small objects, I'd rather fill a build tray with them, and then swap it out every 8 hours when it's done. The belt release stuff really seems to have reliability issues. Or, just use an appropriate manufacturing technique for high volumes...

As I stated in another comment I've done this before. The problem with a build tray full of objects is if one object screws up, e.g. it pops off the build plate, the entire build will end up being scrap. If you're printing a lot then maintenance of the build plate becomes a pretty large issue. I definitely agree that more appropriate manufacturing techniques like injection molding is better after a specific point.

I make cookie cutters, and I want this exactly for that purpose. Each cutter take between 1-2 hours to print, and with a large variety. It would be just wonderful to have a customer order a cookie cutter, have it added to a print queue.

I'm not sure people complaints about printer reliability, since I run my printers at 500+ hours without anything to them, but even still a little maintenance is to be expected in any machine.

How much of a pain in the butt is making sure your prints are food-safe?

My expectation:

Actual issues - 0h

Reddit (/HN) comments - inf. (As much time as you care to spend.)

What do you think is the food safety issue? Don't use a toxic material, contact time is brief anyway, bacterial/fungal build-up in any crevices is getting baked off anyway.

Okay, maybe don't 3D print your own spoons, but cookie cutters? Don't waste time worrying about it.

I have no actual experience with a belt-bed printer so this is pure speculation. I would absolutely believe adhesion/warping etc would be harder to control with a belt, but I also bet it's still within the scope of the usual 3D printer tweaking necessary to get good output. I imagine there are some exciting uses for this sort of printer.

I'm imagining a 100mm x 100mm x belt or so sized printer, for the sorts of custom tchotchke applications that hobbyist 3D printers get used for these days it seems like a good fit. It's maybe easier to make one for each of your friends with something like that vs a Makerbot or Prusa. I bet repeatability in part quality would also be slightly easier to dial in vs printing multiple across a full bed.

It would also be useful for more serious applications. There are plenty of situations where you want many small parts to just come off a conveyor belt after you hit print on your CAD file. Articulated cable guides and fasteners, wing ribs, connectors for extrusions.

Sure it's no revolution, but there are projects I would definitely be more excited to take on if I could automatically manufacture a lot of small parts. I interpret this as a step in that direction. That's appealing.

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