STM32F1/F4 3d Printer board. Worth a kickstarter?

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victor_pv
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STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by victor_pv » Tue Dec 19, 2017 3:45 pm

I posted about porting the 3d printer firmware Marlin to the STM MCUs. I have been contributing code to Marlin, and has been ran in a couple of comercial boards that came with closed source.
In the process, because I wanted to upgrade my own printer to a 3 head mixer extruder, I designed a board with 6 stepper drivers, and I'm now using it in my printer, together with an ESP8266 acting as wireless bridge, and couldn't be happier with it. Everything works, is smooth, can control it remotely, etc etc.

So I have been thinking a lot what I want to do with my board design. I have been considering several things:
  • First is there any need for a new printer board at all? From what I have found, most boards have 4 or 5 stepper drives. With the new mixing heads seems like printers may be needed 3 or more steppers just for the extruders, then there is printers that use more than 3 steppers for the move. So 6 seems to be a minimum.
  • If there is interest in an STM board with enought steppers, should I do a kickstarter campaign to get the funds, and bring the design to commercial quality and volume prices?
  • Should I release the design after a successful kickstarter as open hardware, or should I keep the design propietary to control where it goes?
  • If I go for a kickstarter or other crowdfunding campaign, and fails to get traction, should I still release the hardware designs I have done so far?
My biggest pull is to do the kickstarter, finish the design to be not just good but great or the best, and then release the hardware design and let anyone produce/reproduce it, but with a nice and sound tested design.
But if a crowdsourcing doesn't get funded, should I release the designs? It weights a lot on me what happened to Bobc with the RAMPS-FD: He opened the design from the start, then Geetech and possibly others started producing them, and there are some flaws with that initial design that make it unsafe (the Hotend and Bed FETS can be open from the moment the board is powered up, and if something goes wrong rather than go off, they may stay open, and potentially burn the printer, or something worst...) He has since released better designs, but all cloners are still selling the defective one in Ebay and aliexpress. The result is that a board that could be great was cloned while unfinished, and gave it a bad name, and the cloners are exposing people to fires and damages to their printers.

I'd love to get you guys ideas an opinions:
Experience with crowdfunding, whether an STMF1/F4 based board is a good idea or there are too many out there, whether opening the design if it doesn't get finished is a responsible thing to do, and any other opinions you may have.

To be clear, my day job is not related to this at all, I don't really expect to make much money out of this even if it was very successful, but it would provide the incentive to continue development and the funds to get it to the next level.

All opinions are welcomed, against or in favor of any option, and any experiences that you want to share.

This is a rough description of what I have so far. There are pictures of one of the prototypes in the allpcb review post:
-4 ADC inputs for thermistors.
-4 Endstops inputs (using 3 for XYZ, and an extra left for anything else)
-Heatbed separate power, and 1 mosfet to control it, tested
-2 high power mosfet outputs for hot ends, tested
-1 PWM Fan output, tested
-2 Fan outputs always on.
-6 pololu steppers connectors, tested A4988 and DRV8825
-SDCard and LCD connectors. Tested with 2004 LCD and sdcard display.
-Onboard eeprom for settings (I'm using fram atm), tested
-ESP-01 connector for WIFI bridge, tested with the excellent ESP3D firmware
-Multiple expansion pins, currently using 2 to control a Laser module, and working great.

What I want to add in my next revision, which will be the final or personal usage if I don't decide to go any further:
-Dedicated connector for BLTouch (should work currently fine with the expansion pins I have available)
-Dedicated connectors for Laser/CNC control. Laser needs 1 or 2 pins, CNC normally 2. Currently working with expansion pins.
-Possibly replace the high power TH mostets for SMD ones.

parasole
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by parasole » Wed Dec 20, 2017 3:10 pm

Perhaps reprap forum is a better place for your question... did you investigate what is the add on value for your solution comparing with already present in the field? Although I am interested in this topic, I could not advise you for the reason possible to be true for many other guys over here... as a hobbyist I am looking for solutions I may reproduce myself instead of buying something ready to fly...

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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by mrburnette » Wed Dec 20, 2017 4:11 pm

So I have been thinking a lot what I want to do with my board design. I have been considering several things:
  • First is there any need for a new printer board at all? From what I have found, most boards have 4 or 5 stepper drives. With the new mixing heads seems like printers may be needed 3 or more steppers just for the extruders, then there is printers that use more than 3 steppers for the move. So 6 seems to be a minimum.
  • If there is interest in an STM board with enought steppers, should I do a kickstarter campaign to get the funds, and bring the design to commercial quality and volume prices?
  • Should I release the design after a successful kickstarter as open hardware, or should I keep the design propietary to control where it goes?
  • If I go for a kickstarter or other crowdfunding campaign, and fails to get traction, should I still release the hardware designs I have done so far?
Victor,
I do not have 3D here (yet) so I'm just brainstorming with you:
1st bullet: If the community needs a product, is one not available. Or, are you saying that future implementations will need a new product? Would such a product not be built in-house by the current leading suppliers of 3D?

2nd bullet: I have no experience...

3rd bullet: Open Hardware release w/ Open Software. China is gonna clone anyway; you have to be first and best to control any of the market.

4th bullet: I think this is entirely up to you... but, if you do not acquire funding are you just going to trash the work-to-date? Again, I suspect the Asian market trolls the crowd funding sites looking for profit opportunity... their methods are required reading for all Ferengi business classes.

Ray

victor_pv
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by victor_pv » Wed Dec 20, 2017 4:20 pm

Thanks Ray, that's what I wanted, some brainstorming.
About point 1, I couldn't find any STM based printer board available to use with Marlin, other than STM's own, which is expensive (worth it though, just not for everyone). There are closed hardware/closed source boards, but they have to be reverse engineered since not even the schematics are available, and then again they seem to be expensive for what they offer. But that's my perception, so getting input from other people that has been looking at this subject can help validate whether an STM board specific for Marlin is really a good idea.

On the Ferengi Bussiness Classes, is the first time I see them, but I really did not expect the Chinese to have rule #4 ;)

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RogerClark
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by RogerClark » Wed Dec 20, 2017 8:17 pm

Victor

Not trying to sound very negative, but ...

With domestic 3D printers, I think that the existing , very cheap, solutions are good enough.

If I replaced the AVR + RAMPS board in my Mendel Max 1.5, with a STM32 based board, I doubt I would notice any difference.

The prints are always going to have a corrugated edge, and not be very strong, you can’t print anything with an overhang without adding supports which you need to clean off etc.

Mechanics and general setup of the machine will likely have a much bigger impact on my prints, than the control board, as would using different slicers and slicing settings, or potentially different 3D model generation of the STL file

victor_pv
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by victor_pv » Wed Dec 20, 2017 11:57 pm

Roger, about quality and speed of prints I agree. The main reason I went to design mine was because I wanted 6 steppers, extra serial for wifi, and extra pins for the laser (although those could have been hijacked from endstops), none of those available in my GT2560, and the 6 steppers not available in most commercial boards except the very high end ones, and for that, I'd rather design mine and have fun in the process.

Parasole, I agree with the DIY attitude, that's the main reason I went on to design my own board, for the fun of doing it. I actually got 2 other 32bit boards seating in a shelf, one I got very cheap, and the other was free. But none had the 6 steppers drivers I wanted to use, so rather than buy another board I thought it would be fun to design one and port Marlin. And that's the reason if I don't do a kickstarter or anything like I'll likely open the design, but I'm afraid of cloners going cloning them before the design is fully tested, and just giving a bad name the board.

rsc
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by rsc » Mon Feb 12, 2018 9:49 pm

I dont know the planner.c & stepper.c of marlin, but tinyG implements division and offset of steps for bresenham, and it translates of accumulative errors and then printer is not accurate in printing, affortunatly I solved this problem avoid division after weeks and weeks, open firmwares are really impressive, but much remains to be improved, keep going

ag123
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by ag123 » Wed Feb 14, 2018 7:59 am

i think the board alone would see quite a bit of price competition, as chinese 3d printer kits sells for under usd $200 these days for a complete kit.
there have been some success stories (not necessarily via kickstarter), like the replicape that pairs up with a beagle bone black
https://www.thing-printer.com/product/replicape/
but this started as a winning project sponsored by TI for the startup

you could ship the h/w, firmware w/o providing the sources, and if it is possible to start small and just the board, it may possibly be 'self funded' and do away with the problems associated with campaign on kickstarter etc. i've read some 3d printers inventors tried to start up on kickstarter, then it turns out parts, logistics and manufacturing is where all the costs and problems are, the kickstarter effort eventually failed as an outsourced contract manufacturer couldn't deliver the necessary manufacturing prowess for the costs and is further caught in logistics / parts problems as well.

i'm not sure if this is truly correct as these are merely observation as a 3rd person

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ahull
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by ahull » Wed Feb 14, 2018 3:24 pm

Also worth bearing in mind is the bottom line. What could you realistically expect to make per board.

You are competing against the likes of the cheap $25 Melzi clones for peoples attention.

You either need to beat them on price, or add some extra magic to stand out from the crowd.

Faster, more accurate, more steppers, more sensors, more robust will do the trick to a certain extent, but you also need to get the word out that your board exists, and people have to love it. You are then looking at making boards for high end printers, so expectations are obviously going to be higher. If a crappy melszi clone puffs out half a Havana's worth of smoke, then you shrug and buy another one, but if your $100 board bites the dust you might do a bit more crying in to your beer.
Especially when you consider that I can get a complete low end printer kit (including a melzi 2.0 clone) for not much more than $100.

If you ship a few hundred, and make a dollar a piece, then it isn't worth giving up the day job, but if on the other hand you ship a few hundred thousand, then don't forget to buy us all a beer.
- Andy Hull -

victor_pv
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Re: STM32F1/F4 3d Printer board. Worth a kickstarter?

Post by victor_pv » Wed Feb 14, 2018 3:43 pm

Thank you guys for all the comments and opinions.
The thing that buggers me about not going ahead, is that I believe an STM32 can beat in performance and cost almost anything else running Marlin as of today. Even a basic one as an 103RCT has more pins and ports than most other MCUs, more RAM, very good performance, great prices.

I enjoyed designing it and writing the HAL for Marlin, and my board has been in use now for a couple of months in my printer for both 3d print and laser engraving, and controlled thru wifi thanks to another open project.

On the other hand, there is a limit to the time and effort I can put on this unless I can at least recover some cost.
Now that I have used my current rev for a couple of months and have identified what I can improve on, I plan on making a last revision for myself.
After that, not sure what to do, open it, kickstart it to get funds to finish it to commercial level, or just keep it private.

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