New 3D Printer, busy printing the next thing!

The printer is a ‘resin’ type printer where the print bed is moved (rather than a print head) and is dipped into a vat of resin that is cured using Ultraviolet light.  The pattern to be cured is generated by a high resolution LCD under the vat and selectively passes through UV light from below.  The print bed is then raised to the next position and the next layer is projected on to the last.  It’s a slow process, but very high resolution and, I’m hoping, without the printing gaps that you get with a ‘FDM’ type 3D printer.

The print volume is small, only 4.5×2.56×5.9 inches, but almost all of my printing is smaller than this.  Interestingly, with this type of printer the time it takes to print is entirely determined by the height of the object and the layer thickness, while a conventional 3D printer the time it takes to print is a function of the volume of the printed object and the resolution of the extruder.  Hence, in a lot of cases, the print time will be shorter with this type of printer, especially on complex objects.

So, what have I done since I unpacked this yesterday?

Included with the printer was a sample design file of a mythical WatchTower.  I printed it in a Green Translucent resin purposefully keeping it small to test the resolution:

WatchTower complete with Spiral Staircase in the middle of it.

To give you some idea of the size of this tower, try this on:

WatchTower with some perspective added.

Finally, here is a closeup of the walkway at the top of the tower:

Bird’s Eye view of the watchtower. You can see the stairs descending and the printing on the walkway. Those letters are approximately 150 microns thick…

I soon found that the old electronics were not going to work very well with the new mechanicals.  The new mechanism had a lower resolution movement per step of the stepper motors (to allow faster movement), but this meant the electronics had to be modified for finer steps per revolution (microstepping) and the old electronics were implemented with low cost stepper drivers and could not drive the motors fast enough with the increased stepping rate.  I concluded that it was time to totally redesign the electronics to meet the improved stability of the new mechanicals.

I purchased the electronics in the Winter of 2016 but only recently got around to working on it.

The results are SPECTACULAR!  Not only is the new system a lot faster (3-5X), it is also a lot quieter with the faster switching electronics.  The resolution and accuracy appear to be excellent and MUCH smoother!

Here is the old hybrid system with the new electronics sitting on the table next to the router.  I did this to make sure everything was tuned up before I tore apart the old electronics.

CNC Router after previous upgrade and readying for new electronics.

The results were very promising but only after I also replaced the Z Plate in the Shapeoko mechanicals.  The old Z Plate had too much flex and would not be able to handle the work loads I have in mind.

Here is the new system with the new electronics and enclosure with the wiring cleaned up and routed through cable carrying drag chains.

System upgraded with new electronics and cleaned up wire routing.

Here is a closeup of the new electronics in the enclosure.  The drivers are much more powerful and the power supply for the motors was doubled in voltage (48V) to increase the stepping speed.

Closeup of the CNC Router upgraded electronics.

Here’s the new unit stowed.  It tucks into its spot a lot closer now since the platform closes to full vertical now and I got rid of the attached display and keyboard.  The new system uses Virtual Networking Console (VNC) so I can run the system from my laptop without any wired connection.

CNC Router stowed away. Fits much better than the previous two versions!

Finally, for the first test, I decided to try the Pottery Stamp I’ve made with my original router. I checked in with Matt and asked if he wanted any changes before I made another one.  As it turned out, he wanted a smaller version, which made this new one much more challenging!  Happily, the new router was up to the task and produced a very high quality cutting with walls as thin as 18mil and wall height of 187.5mil (10:1 aspect ratio)!

Having made some progress on my wood lathe, I couldn’t stop there and simply HAD to turn a better handle on the stamp.  Here ya go:

Closeup of first test of the new CNC router electronics. Excellent detail. The wall thickness is 0.018″ (0.457mm) with a height of 3/16″ (10:1 aspect ratio!)

Side view of the first test of the CNC Router, turned on my wood lathe.

I ordered one about 8 weeks ago and it finally arrived last week!  Having built the previous one, with the help of the entire family, this one was a breeze to assemble, although it did take longer in elapsed time doing it single handedly (about 5-6 hours).

I considered going with a different printer, lower cost and not a long lead time, but the quality and features (Auto calibrate being the most significant) of the Prusa convinced me to stick with a winner!

I noticed a few improvements or tweaks in the design since the previous unit telling me that the company is constantly monitoring their product and continuously making improvements – a very good sign!

So here it is:

Finished Printer with miscellaneous parts. Note the mounted camera to the left.

I did make a mistake in assembly that cost me during the calibration cycle (you can see a nasty dig in the right hand side of the platen).  This can be replaced, but, so far, I haven’t printed anything so wide that I would need that area of the bed.  Since then I was able to realign the assembly and was able to perform a good calibration of the unit.  I think this unit has much better print quality than the first one.

I switched cameras on this one, using the small camera designed specifically for the Raspberry Pi.  The reason for this is that I discovered that the camera really needs to be mounted on the platen, otherwise the timelapse videos will drive you nuts as the workpiece keeps moving with respect to the camera.  With this arrangement, the camera and workpiece have the same frame of reference and you can easily see it being ‘built’.

The camera mount came from www.thingiverse.com/thing:2113975.  However I made a mistake printing this in PLA.  The part connected to the platen ‘drooped’ after I printed a couple of ABS parts (which has a much hotter platen).  I’ve since reprinted the one piece in ABS.

Closeup of camera (Raspberry Pi Camera V2.1) and filament dust filter enclosure. This is a hinged piece printed in a single pass.

The 3D Print server works very well with this camera:

View of screen running 3D Printer server, complete with video!

Having a queue of projects and add-ons for the printer, I spent the next couple of days printing various items…

Close up of Extruder Filament guide adapter plate. Teflon tubing connects this to the filament dryer filament feed guide. Also note the filament dust filter. Normally this will be located just before the upper feed guide as the tubing will keep the filament dust free after that.

3D printed drip valve, just waiting for the PCB to control it.

Miscellaneous parts printed on the new printer. Overall the quality appears better than the printer at the House In The Woods. Probably due to better calibration and newer printer firmware.

With my limited space at LHV, I knew that the printer would be relegated to the garage/workshop, which is both dusty and humid.  Humidity and 3D filaments don’t mix well – or, I should say, they mix TOO well with 3D filaments LOVING to absorb any moisture in the air.  So, I needed a setup where the filament was kept in a dry spot.  After some research, I discovered that Food Dehydrators are very popular mods for 3D printers and this led me to this next series of photos…

Filament dryer base (Cake Transporter) with final modifications sitting on top of unmodified Food Dehydrator. Note lazy susan bearing and 3D printed hub to keep spool aligned and turning easily.

I found a Food Dehydrator and a plastic Cake Transporter that appeared to be ‘right sized’ for this application.  The Food Dehydrator was PERFECTLY sized with the cake transporter base fitting just inside the rim of the dehydrator, I didn’t need any modifications for the dehydrator base.

I was then able to cut out openings in the cake transporter base with a flush cutting router bit in my trim router.  The lazy susan, used to allow the spool to spin freely, was also ‘off the shelf’ and it just took a couple of simple 3D printed add-ons to complete the dryer!

Filament dryer base (Cake Transporter) with final modifications sitting on top of unmodified Food Dehydrator. Note lazy susan bearing and 3D printed hub to keep spool aligned and turning easily.

Filament Dryer with spool and filament guide. The fitting holds a teflon tube that guides the filament down to the extruder.

Completed Filament Dryer, drying a spool of PLA.

I’m trying a simpler enclosure (a large cardboard box) this time around, but I may go the same route as HIW as the cardboard box is a bit too rickety.  We’ll see and I’ll update this when I reach a conclusion…

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The sequence is supposed to look something like this (from Kester EP256 datasheet):

Here is what I was able to get with this oven:

Here is the profile I’ve gotten with a bit of tweaking.

Close enough!  It takes a bit longer to reach target temperatures than the professional equipment, but mine uses FAR less power, and, what the heck, why do I care if it takes 5 minutes instead of 4 minutes to solder as many circuit boards as I have to do?

Here’s what the oven looks like:

Front of the oven. Controls are timer, mode (I use convection mode), and temperature (max’d out).

To convert, I had to take off the cover and rewire the controls.  I disconnected the silly neon lamp on the front of the oven and used its wires to power my controller and then cut the main power line feeding the thermostat and branched off both sides to the solid state relay I use to control the heating element in a more sophisticated way.

Inside of the oven control section. Note the use of high temperature wire and porcelain wire nuts.

Even though I have an embedded computer controlling the heater, I decided to leave the original timer and thermostat in place to provide a layer of safety to this tool (even though it won’t be left unattended – unless I have to go to the bathroom, the UPS man is delivering something, etc etc etc).

To monitor the temperature accurately, I installed a stainless steel probe K type Thermocouple.

Inside of the oven with the shelves removed. You can see the stainless steel thermocouple that monitors the temperature right at the tray holding the workpieces.

Here is how it is mounted from the back.  I was fortunate that this particular oven had the extended back (to provide room for the probe) AND had a little bumper installed exactly where I wanted to put the probe!  I just removed the bumper and ended up with a pilot hole to drill for the probe!

View from the back. Note how the oven extends outward, providing room and a pilot hole for the probe.

The new controller was built from an Arduino type processor called ‘Moteino‘.  It is a very small circuit board and usually has an onboard radio for wireless applications, but, in this case, I didn’t need the radio.  It’s very easy to program this module, very small footprint, and, short of making my own PCB, about as low cost as I could get!  Of course, now that I have a reflow oven, I might be able to make my own board…

Mounted the new controls on the side. Shown is the new controller and solid state relay, which switches power to the heating element, mounted on a thick piece of aluminum to absorb any heat it generates.

Close up of the controller. The red circuit board is the ‘smarts’ of the device while the circuit to the right converts the thermocouple signal to an accurate digital value used by the controller.

The red and green lights in the upper right are used for status.  The red light’s intensity is proportional to the current temperature in the oven.  The green light flashes based on which phase the sequence is in. And BOTH lights flash demandingly when I need to open the oven door to accelerate the cool down.

Here it is, all buttoned up and ready to solder circuit boards!

Just another day at the office…

Here’s my current ‘activity’ as I’m simultaneously debugging code on 4 different processors, 3 of which have radios that are communicating with each other and one is our home server containing our webserver and MySQL database (where all the data is supposed to be going).

Amazingly, it’s all working!

Cheers!

So, without further ado, let me introduce the Little House in the Village Webserver:

The Little House in the Village Home Server

It’s there, really!  See that little clear box in the foreground…

Here’s a closer view…

View showing the Server and its hard drive.

Closeup of the top of the Server

View showing the network and power connections.

View showing the USB, SD card, and microHDMI connections.

So you think this looks like a toy?  Well, its a 1GHz ARM Cortex-A8 processor, 512MB RAM, 2GB Boot MMC memory, micro-SD slot (where I could put up to 32GB of SD memory), 10/100 Ethernet, USB 2.0 Host & Client connections, and HDMI video output.

Natively it will boot a Linux desktop based on Angstrom without any additional hardware.  I have it set up with a 2GB boot SD Card which boots up an ubuntu Linux Server and then switches over to a 160GB hard drive attached to the USB port.   I currently have it set up with Apache2, MySQL 5.5, PHP 5.1, and WordPress.

I don’t need a local display or keyboard since I can login over the network via ssh.

Here are some various screen shots…

Logged in, showing the contents of a system directory.

Showing system stats. Not very busy right now...

The Little House in the Village Web Portal

Oh, and one other thing.  This little powerhouse consumes about 4 watts (including hard drive)

 

 

In that project I added the plumbing to monitor Water Hardness, a Water Usage meter, and Water Pressure monitor port.   With the completion of the Water Monitor, which, I might add, I completed it ahead of schedule!¹, I can now, via our Intranet:

• Check on water usage,
• Check the water pressure (after the water softener and water filter to see if either are clogged),
• Check the relative water hardness,
• Check the status of the water softener cycles (to see if I need to add salt),
• Control the water softener cycles in a more closed loop way (either via hardness threshold or simply by gallons used since last cycle),
• Remotely trigger a water softener cycle,
• And, just for fun, monitor temperature and humidity in the House in the Woods crawlspace!

All of this is achieved with a GREAT new module (RTX4100) that provides, in a package less that 1 sq inch, a WiFi radio (complete with TCP/IP stack AND built-in PCB antenna), a 32 bit ARM processor (separate from the radio processor), a whole bunch of configurable I/O options (including GPIO, ADC convertor, timers, etc.), 24+KB of user program storage, and about 6KB of RAM, and 512 words of non-volatile storage.

If you think this doesn’t sound like much memory, with this project I have implemented the Water Monitor data acquisition, control, and logging function AND included an HTTP mini-server (complete with NTP client) so that anyone can query the monitor from a standard browser.  To the module, I added a temperature and humidity sensor, water hardness measuring circuit, water pressure gauge interface, connection to the water meter, interface to control and monitor the water softener cycling, and 32 KB of battery backed up RAM to log up to a week’s worth of samples in case the Intranet server is temporarily out of commission.

Here’s what the project looks like:

Next up: Add the code on my Intranet server to save the sample data to our database so that we can monitor water usage, etc., over a longer period of time.