After purchasing your shiny new Ember 3D printer, you decide to print the biggest x-y surface area 64x40mm has to offer because you want surface and you want all of it. Hurried fingers swipe and click.A solid rectangle. An STL. A stoic orange and grey cylinder.
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Closer. The circle of LEDs dance before you while rectilinear plane after rectilinear plane flow through your imagination.
Is there enough resin, is the build head clear?
You've waited whole minutes for this moment. START! The Z-axis descends like a nonchalant eagle to a delicate perch, the resin tray rotates to position, 22mW/cm^2 of 405nm light blast on to the build area. At long last!
Resin tray jammed
The blood drains from your face. Resume. Resume! The tray is stuck fast, your grand visions reduced to 25 microns of hardened SLA resin between an aluminum plate and a slab of PDMS.
But don't loose hope yet! With a 2mm allan key, a no. 10 torx and a Phillips head screwdriver you too can likely decrease the life your Ember stepper motors and PDMS windows all in the name of moar surface area.
Step 1: Gather Necessary Implements
2mm allan key.
No. 10 torx screwdriver
Small philips screwdriver (ceramic or plastic helps but not necessary)
Step 2: Remove Front Panel
There are two M3 button head machine screws on the side. Remove these first.
Two plastic screws with no. 10 torx head on the bottom. Remove these second.
When you pull off the front panel two star washers that live between the front panel and the frame which were being held in by the M3 machine screws will fly off in random directions because you didn't read this until just now. Those washers help with radiated emissions which the FCC likes to regulate so that everybody can have happy working electronics. Neat!
Step 3: Adjust the Current Limiting Potentiometers
Like all things designed correctly, the Ember features a simple way to increase the amount of power its motors use far beyond the specified recommended operating point.
On the left side of the PCB inside of Ember are two small adjustable potentiometers they have Philips head tops, but I find a flat head works just as well. These control the reference voltage for the stepper motor drivers that ultimately decides how much current the driver will let into the stepper coils. We're only interested in the leftmost potentiometer circled in blue. It's the one that controls the build plate rotation.
Now we don't just want to crank the reference voltage all the way up in a fit of passion over surface area. If too much current goes into the coils the motor will get too hot and it will overheat rendering the motor useless until it cools down or even permanently.
To mitigate motor death, we'll pull out our ever faithful measurement friend the multimeter. We're going to measure the voltage between ground (the screw on the PCB circled in green) and the leftmost pins sticking up directly behind the potentiometer circled in red (they have a jumper between them).
Keeping the multimeter connected, we're going to increase the voltage by turning the potentiometer. It's a bit finicky to get in to a particular spot especially if you're using a metal screwdriver. I've found that 1.2V reduces most jamming problems. If you keep having jams you can try more, but be careful! If the resin tray is ever very easy to turn while the printer is on the motor is overheating and you should turn down the reference voltage or cool the motor somehow.
Step 4: PRINT SURFACE AREA
Now your Ember should print larger surface areas happily. I usually leave the front panel off when I have the motors over torqued just so they don't overheat. If you do leave the front panel off, be extra cautious about cleanliness around the Ember and make sure you don't drop anything conductive inside that could short any of the components.
Some more tips for printing large surface areas:
- Slow the Z-axis Approach Velocity down to 3000 micron/second (in all layer types!)
- Add a Delay After Approach of 1-3 seconds(in all layer types!)
- Hollow your part out to avoid too large of a surface area to begin with
A lot of issues with printing large surface areas arise because extra resin that doesn't flow out from in between the build head and PDMS gets cured. Slowing the Z-axis down and adding a delay after approach let that resin escape.
db_lewis made it!