More money, more reliability?

[Oxalainen]

As I have partially commercial interest in 3D printing, my main concern with the machines is productivity. Which leads me into a question, do more expensive 3D printers offer more reliability in long run, than cheaper 'hobby' level machines?

I've had 4 printers so far, and they've all been sub-300eur 'hobby' grade gadgets. However, I print with these machines a lot, usually 12 to 20 hours per day, 5 days a week. I'm beginning to think that's simply too much for them to handle, as my first printer (Ender-3 Pro) went kaput after about 18 months, and my second printer (Mingda Magician X) held on for a little over a year. Now I'm in serious problems with my Artillery Sidewinder X2 and Sovol SV-05, although I'm thinking their issues are mostly due to my workshop conditions.

I wonder if a slightly more expensive 'prosumer', setup in rough 400 to 700eur price range, would offer more long-term reliability? I'm eyeing printers from Qidi-Tech and FLSun, but most of the times the reviews online focus only on structural design and nowadays increasingly on speed. There's not much long-term reviews out there, and before investing big dosh into more expensive machines, I'd be interested in knowing if I'm running into same issues with those gadgets in next couple of months?

[Antipodean]

Well, I guess the best way to look at this is what the tax department will let you do for development of your business and what deductions they will give you. I would have thought that they would allow a write-off of the capital cost pretty quickly. If using it essentially full time on a work day you could probably write it down in a year for an item under 1,000 euro I would have thought.

But perhaps one of the best things to do is go to a 3D printing fair (again, surely a tax deductible expense) and talk to sales reps to see what sort of repairability/maintenance/failure rate information they have. I don't have any idea what fairs there may be in your vicinity, but would have thought that there would be something in Sweden, Norway, or perhaps Germany or Denmark that you could get to without too much expense and time away from the workshop.

Going to a fair would also allow you to assess the possibility of UV resin 3D printers (which can produce better detail) as well, and maybe add a laser cutting machine to your capabilities.

[CrazyIvan]

An interesting question. I'm an engineer, so I think we can make progress by discussing the relevant points. As I see it:

Key Components

• Controller
• Stepper motors (X, Y, Z, extruder)
• Nozzle heater
• Hot-end fan
• Build platform heater
• Build volume heater/fan
• Electrical interconnect
• PSU
• Mechanical parts (lead screws, drive belts, bearings)

From the point of view of reliability, I think we can ignore the controller. It's an electronic assembly, and although an external fault might damage it I don't see any reason a "pro" controller should be physically more reliable than a "hobbyist" controller. Granted a "pro" controller might have better functionality, but that's not the issue here.

All kinds of motor have duty cycle and endurance specifications, stepper motors being no exception. Duty cycle is how long it gets used in any particular interval of time, and defines how hot the motor might get (depending on load). If you try to drive the same load with a small motor or a big one, the small motor will get much hotter than the big one... but space might be limited to accommodate a big motor, and they cost a lot more. This I think is where there could be a big difference between "Pro" and "Hobby".

The nozzle heater, and thermocouple for temperature monitoring, are (I think) pretty robust. A difference could be the maximum rated wattage, which will set the limit on the volume of filament which can be melted per second and therefore the speed of printing. Even if the motors can move the nozzle at (say) 500mm/s, that's of little use if you can't feed that much filament through the nozzle.

The hot-end fan is just a fan, and manufacture is pretty standard with only the one moving part and a magnetic bearing. Nothing to be gained here.

Build platform heater: nothing to see here. Temperature is not going to the sort of extremes which might trouble reliability.

Any build volume heating and extraction/cooling, comments similar to the above.

The electrical interconnect is, IMO, a BIG issue. This is where I've had the most (in fact, all) trouble: where it is necessary to provide electrical connections to moving parts. My observation of the hobbyist Tina2 is that very little consideration has been given to managing the consequences of flexure of the umbilical cables which connect the controller to the hot-end (heater, thermocouple, fan, proximity sensor) – which moves in X (other models might be Z as well, according to design), and X carriage (stepper, home switch) – which moves in Z. The Tina2S has a build platform heater as well, which moves in Y.

Connectors and electrical joints must not be subject to bending, so cables should be physically secured ("strain relieved") separate from the connector itself. Cables have a minimum bend radius which must be respected to prevent premature fracture, but cheap cable does not have a specified minimum bend radius. Even if the minimum bend radius is respected, that is for static installation, and repeated flexure (as per the constant motion of a hot-end) will ultimately fracture the cable.

This is a particular problem for high-temperature insulation as used for the nozzle heater. The Tina2 runs this cable though the umbilical, but the insulation is stiff and prime for fracture. I believe the Tina2S uses a more flexible cable in the umbilical and an intermediate connector at the hot-end to the actual heater block.

The main concerns for mechanical parts are drive belts, which can wear or stretch, and bearings. there are bearings in the idler pulleys, but more particularly there might be linear bearings which guide the various motions in X, Y, and Z, if these motions are guided by sliding on some kind of rail rather than by guide wheels. Rotary (ball) bearings are much less subject to wear than sliding linear bearings (linear ball bearings exist but are expensive), and in "hobbyist" printers I guess the linear bearings might even be sacrificial, if no provision is made for periodic greasing (the Tina2 comes with no maintenance instructions).

The quality of bearings is critical to maintaining the alignment and motion of the X Y and Z axes over time.

My bottom line is that you can't expect quality components at the cheap end of the market, but if I was going to spend a lot more I would want to know what that money was going on and whether the points above are addressed by the engineering in the prospective purchase or what compromises have been made for cost at that price point. It could well be that at the "Pro" end, everything above has been considered... but then again, perhaps it hasn't.

[CrazyIvan]

Another point: lifetime of the motors (and possibly other components as well) is extended if operated significantly below their maximum performance. Just because a printer can run at 300mm/s (or whatever), doesn't make it necessarily a good idea.

[Oxalainen]

Well, I guess the best way to look at this is what the tax department will let you do for development of your business and what deductions they will give you. I would have thought that they would allow a write-off of the capital cost pretty quickly. If using it essentially full time on a work day you could probably write it down in a year for an item under 1,000 euro I would have thought.

But perhaps one of the best things to do is go to a 3D printing fair (again, surely a tax deductible expense) and talk to sales reps to see what sort of repairability/maintenance/failure rate information they have. I don't have any idea what fairs there may be in your vicinity, but would have thought that there would be something in Sweden, Norway, or perhaps Germany or Denmark that you could get to without too much expense and time away from the workshop.

Going to a fair would also allow you to assess the possibility of UV resin 3D printers (which can produce better detail) as well, and maybe add a laser cutting machine to your capabilities.

Good points. I was offered a small development grant for investments last year, because I'm a small business in rural rarea. However, for a 700eur machine that would had been approximately 150eur, tops. And at that time I didn't have 450 to spare (well, still don't, LOL!). During the COVID crisis businesses of different sizes were eligible for different aids here, but later turned out many of them were issued under false premises and the businesses had to pay lots of those aids back. I never applied for one, and all that hassle afterwards made me a bit sceptical about government fundings. Had I received a grant and someone at the RedTape factory later on decided that it wasn't applied with correct form, a three or four-digit figure back to government would had been a hefty bill for small business like mine.

A fair or expo would be indeed good idea, I'm not sure what there are in my neighbourhood but need to check out! I think they don't do much of those here for this level of gadgets, only for five-digit priced industrial machinery. I've noticed printer vendors are not necessarily always honest about these, I asked one local a while ago what would they recommend and they offered me a Creality K1C. A machine which had widely controversial reception on the interwebs, plus having had one Creality machine before I wasn't too interested in buying more expensive one and then doing 'necessary' upgrades for it couple of weeks later.

[CrazyIvan]

During the COVID crisis businesses of different sizes were eligible for different aids here, but later turned out many of them were issued under false premises and the businesses had to pay lots of those aids back. I never applied for one, and all that hassle afterwards made me a bit sceptical about government fundings. Had I received a grant and someone at the RedTape factory later on decided that it wasn't applied with correct form, a three or four-digit figure back to government would had been a hefty bill for small business like mine.

That sounds familiar, I think pretty much the same happened here (UK).

[Oxalainen]

Another point: lifetime of the motors (and possibly other components as well) is extended if operated significantly below their maximum performance. Just because a printer can run at 300mm/s (or whatever), doesn't make it necessarily a good idea.

I'll quote just this post, as the previous one was... Well, a bit 'wordy'. But that's all right, I like wordy!

Agreed, I'm not exactly sure why the printing speed gets so much attention in advertising nowadays. Well yeah, I can understand why it's been advertised, of course insane print speeds look snazzy, but personally I'd prefer a decent balance between speed and quality.

Yup, in more expensive machine I'd prefer seeing linear rails over belts. I've had generally little belt issues with my 3D printers, but in my late CNC router the belt lasted only a week. Granted, that machine had more than a few design flaws (or shortcomings) to begin with, but still.

I'm not an engineer, but from engineering point it makes me puzzled why the printers use different metals for the components which handle most of the heat? I mean, the nozzle is often brass, but heat block is aluminium and then the heat break who knows what. I suppose smarter people than me have thought about this.

Also, I believe there's NOT much of 'paying for the badge' phenomenon in 3D printing business, like there would be in smartphone or car market for example. I think right now the 3D printer market is too competitive and not that many makers are sitting on a pedestal -yet.

[CrazyIvan]

I'm not an engineer, but from engineering point it makes me puzzled why the printers use different metals for the components which handle most of the heat? I mean, the nozzle is often brass, but heat block is aluminium and then the heat break who knows what. I suppose smarter people than me have thought about this.

I'm only guessing, but brass is good because it is easier to machine into the shape of a nozzle (therefore cheap), and soft so it won't gouge the build platform so much if an inexperienced operator allows it to ground. Hardened steel nozzles are available for when the filament type warrants the extra expense.

Aluminium makes a good heater block because of the low thermal mass. If it were steel it would take longer to warm up and cool down, but also it would make the hot-end heavier and therefore more difficult to move, so slower or requiring higher power.

The heat break is I think a steel tube with an aluminium heat sink (heatsinks are typically aluminium throughout the electronics industry, usually extruded sections). Steel is a relatively poor conductor of heat, so appropriate for the heat break and also a stiff support for the other components.