In over my head with chocolate printer electronics!

Hey,

I am currently designing and building a chocolate 3D printer, but I am having trouble choosing electronics because there are so many options.

Here are my requirements:
• I need 4 stepper motors,
• 3 (maybe 4) end-stops,
• 1 or 2 heater (I am not sure yet), although this does NOT change the number of stepper motors.
• 2 (or 3) fans
• 2 (maybe 3 or 4) thermistors

• An LCD would be nice
• LED lights could be fun

Preferably there is an all in one solution for an electronics board.

Can anybody suggest and give a link to a specific RepRap electronics board and power supply?

Thank you in advance!
~Evan

RAMPS is your best bet for a general purpose board, paired with an Arduino Mega 2560. It's a mature platform and easy to use. There are limitations on the number of things you can drive with it, though. Most printers have a single extruder / hot end and a single fan, where the fan is controlled by the firmware. The RAMPS can drive that, or two extruders with no fan. Obviously you can plug more fans directly into your power supply, but they won't be controlled by your electroncs. RAMPS on the reprap wiki.

If you need more, take a look at the RUMBA. It can support up to three extruders and two fans simultaneously and has an inbuilt Mega 2560.

You can connect an LCD smart controller to either a RAMPS or RUMBA.

In addition to the board, you'll need stepper drivers. Typically Pololu A4988s, although there are newer DRV8825s around that are an improvement.

For a power supply, the three basic options seem to be an XBox360 power supply, a PC power supply or a power supply typically used to drive chains of 12v LEDs (all listed on the reprap wiki). I personally use the LED power supply as it's more cost effective - but make sure you get one capable of handling the load.

Where can you buy all these? Ebay, amazon, or try the list of suppliers at the reprap wiki.

---

[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.

Ramps with 4998 drivers Imo. Even if you could find a use for three extruders, you'll find it hard to drive them all with the available software.

Question for each of you
Is chocolate hard to melt? I mean does it have a narrow band ewen Molton and burnt?

Does anything support the 8825's 32x Microsteps? They seem price wise not far off the 4998

drv8825 is a drop in replacement, all firmware support it, you just double the number of steps per mm and set the correct jumper combination

So you would just switch the jumpers to some new combo which represented 32ms and off it would go?

Any down sides to 32 x microstepping? Torque, etc?

And sorry to hijack your chocolate thread, it's all useful info

Quote
UkIan
Ramps with 4998 drivers Imo. Even if you could find a use for three extruders, you'll find it hard to drive them all with the available software.

Question for each of you
Is chocolate hard to melt? I mean does it have a narrow band ewen Molton and burnt?

Does anything support the 8825's 32x Microsteps? They seem price wise not far off the 4998

I am considering using a RAMPS pre-assembled kit. this comes with everything that I need (the arduino mega, 3 end stops ect.) and comes with the Pololu A4988 Stepper Driver, which seems to be the standard.
https://ultimachine.com/content/ramps-pre-assembled-kit-complete.

The price may be a bit high, but it is completely assembled which is nice.

Chocolate has six crystallization stages and in general to cool quickly and have a "snap" when you try to break it off (as opposed to crumbling the second you touch it) you need to heat it up to the fifth crystallization stage. There is an incredibly small window for this melting temperature.

From Wikipedia
Crystal------- Melting temp. --------- Notes
I ---------------17°C (63°F) ----------Soft, crumbly, melts too easily
II --------------21°C (70 F)-----------Soft, crumbly, melts too easily
II --------------26°C (79°F) ----------Firm, poor snap, melts too easily
IV ------------- 28°C (82°F) ---------Firm, good snap, melts too easily
V -------------- 34°C (93°F)--------- Glossy, firm, best snap, melts near body temperature (37°C)
VI ------------- 36 °C (97 °F)-------- Hard, takes weeks to form

Quote
UkIan
And sorry to hijack your chocolate thread, it's all useful info

haha its fine! This is the kind of stuff that I am trying to learn about right now!

Interesting, I guess you heat it to the lowest temp it flows and only heat it to stage five at the nozzle?

For ramps, they pretty much all come assembled. The Stepper drivers slot in sockets, then all the wires for thing plug onto various pins. The price didn't look awful, but could be cheaper I think. Are you in the states? There are a surprising number of English and European people here and I keep assuming everyone is.

>Any down sides to 32 x microstepping? Torque, etc?

lower max speed.

The Arduino can only put out so many pules per sec, 1/32 requires twice as many step pulses as 1/16 so half the max rate.
This does becomes a real world issue if your going fast. some say its also partly just a bad coding issue. but people are using arms processors to get higher speeds with average code.

I don't think this would cause an issue for a chocolate printer, I suspect that will be slow by necessity

Edited 1 time(s). Last edit at 10/09/2014 03:06AM by Dust.

I'm all for throwing processor power at a problem

---

Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

Quote
3dkarma
Obviously you can plug more fans directly into your power supply, but they won't be controlled by your

Out of the box it only supports a maximum of 3 heaters or fans if you need PWM control of higher current devices. There are additional servo and aux pins that will give you either digital (full on/off) or pwm control but you'll need to buy or design your own controllers to utilize these. By doing so, you can easily satisfy your requirements of additional fans (if you needed the ability to control them), LED lights, or really anything else you might want.

Quote
UkIan
Interesting, I guess you heat it to the lowest temp it flows and only heat it to stage five at the nozzle?

For ramps, they pretty much all come assembled. The Stepper drivers slot in sockets, then all the wires for thing plug onto various pins. The price didn't look awful, but could be cheaper I think. Are you in the states? There are a surprising number of English and European people here and I keep assuming everyone is.

Yes. I'm in Pennsylvania. I am planning on keeping it at 30-34 degrees Celsius, not heating it in two stages, although that is an interesting idea. If I use nichrome (resistance) wire for heating, I wonder if I can put more of it near the nozzle, and then put the thermistor directly at the nozzle to have the effect of keeping the chocolate near the nozzle at the right temperature and the other chocolate slightly cooler. I am going to use a 60 or 100 cc syringe inside of an aluminum tube for the extruder with the nichrome wire wrapped around the outside.