Cube3 teardown - Electronics

Here are some pics of the LCD and controller boards in the Cube3 during my initial teardown. (I found it strange that I couldn't find any detail of what the MCU and motor drivers were for this guy while I was researching it online.)

To get to the controller board and LCD, you must remove the outer shell of the printer. I simply followed the teardown steps from the OpenBuilds forum thread.

Cube3 with outer plastic shell removed.

To get the front shell off, you have to disconnect the cable to the LCD first.

The LCD and button board are attached to the front plastic shell. To remove the board, unscrew the 4 small Phillips-heads (and don't lose the button, it's not connected to anything!)

It looks like a 3" LCD from a cell phone, with a 4-wire resistive touch screen. A company called "Lincoln Technology Solutions" made the module.  

There's a 16-pin QFN part on the module that is probably the controller for the backlight. I assume the interface to the LCD itself is SPI, considering the small number of wires. 

The main controller board has 5 motor controller chips on it. One for each axis and extruder. 

The motor controllers are TI's DRV8811. The 8811 seems to be the little brother of the much more common DRV8825. It supports a peak current of 1.9A and 1/8th microstepping, compared to the DRV8825's 2.5A peak current, 1/32nd microstepping. (I've read that the DRV8825 really shines at 24V, which would explain why this system runs at that voltage instead of the more standard 12V.)

The biggest surprise of this teardown was the make/model of the controller micro. Instead of running on the prolific AVR architecture, which powers almost all hobbyist 3D printers at this point, or an ARM Cortex M3 or M4, which are the up-and-coming contenders, the Cube3 is powered by a Microchip PIC32! That's definitely a shock. The PIC32MX695F512L is an 80MHz MIPS M4K micro with 512K of flash and 128K of SRAM. The peripheral set, other than USB host, is about equivalent to an AVR/ low-end ARM: 16-channel 1 MS/s 10-bit ADC, 5x 16-bit timers/PWM, 8-channel DMA, 2x comparators. The kicker is it's priced around $10/each (in single quantities)... which is what an AVR MEGA2560 costs, and is probably double that of an ARM. (The M3 in the Monoprice Mini is less than $1 per.)

The wifi module is also made by Microchip. (I didn't look this one up because it's not exciting.)

There's also a Bluetooth Low-Energy module on the controller board. I haven't used the mobile phone app for the Cube3, but that's probably what this is for.

3D Systems Cube3 - Post Index

I'll be doing a series of posts about 3D Systems' Cube3 printer. I've been posting a lot of info in a Facebook group, but the post is getting long, and not easy to navigate. So I'll be re-posting that stuff here, along with all my new investigation. Since I already have a large backlog, I will probably post things out of order. This post will act as the "table of contents" for all the posts, so it will be easier to find what you are interested in.

01 - Cube3 Intro and Resources
02 - Cube3 Filament Cartridge Intro
03 - Cube3 Print Bed and Quality
04 - Cube3 Filament Cart Teardown
## - Cube3 Teardown

• Electronics
• Hardware
• Bed

## - Cube3 Filament Cart EEPROM Reading

SMD Capacitors in Bulk

I'm planning on adding a SATA connection to my Pogoplug Mobile, possibly promoting it from "thing in a box that I've already hacked and become bored with" to NAS box I would use daily.
(I'll be using this thread as my guide, although it's a bit sparse.)

The only thing in my way is a little SMD soldering, which is more of an attraction than anything else at this point. Unfortunately the mod requires adding some 0402 components, which is not a size I have on-hand. But take heart! It just so happens I am in the middle of assembling an order to Digi-Key. (I usually order from Mouser, but Digi-Key has a larger selection, and it just so happens this time aroudn I need some stuff Mouser doesn't carry.)

If you're never ordered from an electronic component retailer before, they normally offer large price cuts the more you buy. Often they won't even sell you less than an arbitrary minimum number. (If you look up a part on findchips, the lowest price is almost always at Verical, the "clearance aisle" of Arrow, but you have to buy several dozen to get that price.) This is the reason why we need services like Tindie and Kickstarter, as everything in the electronics industry operates this way, making it prohibitively expensive to make only a couple of anything.

I'm well aware of how this all works, but when I went to hunt down some 0402 caps and resistors this morning, I found the bulk pricing on them very odd.

Their price for a single 0402 10nF cap is 10 cents. Seems a bit excessive, but you always get gouged for small quantities, and they are X7R (low variation over temperature) and a name brand. I only need maybe 5 caps, but I've learned that the smaller a component is, the more spares you should buy. So I should probably buy around 10, then. The bulk price when buying 10 or more drops to 1 cent each. So let me get this straight, buying 10 of these caps is exactly the same price as buying just 1. How is that possible?

I looked at the next tier up; when buying 25 or more, the price drops to 7/10 of a cent each, making buying the minimum for that tier a total of 18 cents, which would be less than the price of 2 single caps. The next tier up is 100 caps for less than 5/10 of a cent each, with the minimum purchase a grand total of 47 cents.

So I could buy just the 5 caps I need for 50 cents, or I could buy 100 caps for 3 cents less.
Makes perfect sense!

Tiny printed lab jack.

Dirt-cheap filament dryer.

I've been killing myself trying to figure out an easy way to dry out my PETG filament. (My big printer is in the garage, and the filament absorbs the moisture in the air so quickly that it's almost unusable if left out overnight!) I stumbled on the plans for this dryer on the Taulman site, otherwise I probably wouldn't have trusted that it works.
I'm using a 40W halogen globe, and it stays consistently between 100-105°F. There's room for two spools, and after a good 8 hours in there, my PETG is usable again!
(And it's much easier to build than a toaster oven/SSR/PID controller setup).