3D Printing parts for the Printer



At this point the printer isl making more parts for itself. Teal (my wife) compared it to Frankenstein adding his own parts after he had an arm attached.

One of the first part sets was to make a case and mount for the display. The case turned out quite well, but the design of the bracket to mount it to the frame was unusable. So I will be searching for another or designing one myself.

The advantages of being able to walk away and let the printer just run and return to a safe state are huge. With the print head on the CNC router, I had to keep checking on the progress and shut it down at the end as the software could not control the print head heater . Now not only is it running and shutting down properly I get messages on my phone confirming the status. With Repetier host https://www.repetier.com/, you can add an app to your phone, Repetier Informer, and get notifications of start, stop, faults and progress (among others). So today as I was again multitasking,getting the spring gardening done and wandering about the yard, I was getting notifications so I could check up on the printing status while finishing the placement of 20 yards of wood chips and propagating many perennials. This was to gain more flower beds with perennial plantings and reduce lawn area and Buckthorn thickets. I was doing my Earth Day yard work.

Today the printer was making cable chain. I am not sure if this a good trade-off of time vs cost. Cable chain is used to make a nice flexible assembly to hold your wires / cables for moving devices. For the CNC router  I bought the cable chain from an eBay supplier in China. For the 3D printer, the printer itself is making the cable chain links but I have to do the part clean-up and fitting. The printing is not yet tuned in well enough to avoid a lot of hand work on these parts.

Spool holder to hold the filament spool while printing.: http://www.thingiverse.com/thing:1959643/#files.  This replaces the ugly aluminum rod seen earlier in the photos and removes obstructions. This is a very nice and simple, functionally designed part. “Frankenstein printer” did well on making this appendage.

Cable chain. This supports the wires going to print head in a neater manner than the spiral wrap. I am using the part designs from: http://www.thingiverse.com/thing:611593/#files . I wanted cable chain that would be open on top so I do not have to re-run the wires in the frame with the need to then disconnect re-connect everything for the print head. We will see how this turns out. The notches look like they will need some fiting for the snake shaped cable retainers (cable ties bay do instead). Cable chain parts are slow to print . A set of 16 links takes about 5 hours. Then there is some tedious hand work to clean up the parts and make them fit together well. I think 2 sets of 16 links, plus the end parts should suffice for the print head cable chain. Here is the first set of links fitted together, roughly straight and as a U.


3D Printer is Running!

The printer is now running It is roughly assembled (as you can see) and now it is time for fine tuning and making parts for itself. I love it when a tool is at the state where it can help finish its own build or rebuild making parts. Cases for the boards, cable retainers, cable covers, cable chains, proper spool support are all on the short list.

There has been a bit of additional grey hair added getting here:

The Rambo control board will not connect at all via USB3. It must be a USB 2 connection . This is the case for both the Arduino downloads and Repetier control software. I did not pay attention when I originally programmed the board and then subsequently rearranged the USB ports…

Along the way the first Rambo board stopped communicating via USB. Many tries to get this going, re-download drivers, try to re-flash the USB chip but to no avail. I ended up returning the first one (still barely within the 30 day amazon return period) and got another. So far so good. I was able to get it programmed and it is running well so far.

As mentioned previously the thermocouple adapter wont work with the 12864 display. So I have jammed a thermistor on top of the heater block as I don’t want to pull out the thermocouple temporarily and risk damaging it and the thermistor is working OK for now. It is still off by about 15 degrees, too hot, and the temperature control overshoots. However the adapters are on their way.

The new nozzles form Micron finally came. It takes almost 4 weeks from Israel with normal shipping. I am currently using the high flow 0.5mm nozzle.

Fan for the print head heater must be directly connected to 12v. Not fan 0 or 1 . It needs to be always on. Not doing this lead to new and novel ways to jam the filament.

It pays to double check the tooth count on the gears. The first test cube was well undersized and over-extruded. The steps per mm settings are now corrected.

12v power supply was just not enough to get the print head up to temp. I needed to switch to 24v.

Still need to find a better way to adhere the cork to the bottom of the heated print bed.

The plain glass rectangular cutting boards form Amazon are working well as build plates. So far printing the PLA to the clean glass with no additives. Clean with denatured alcohol.  On the old setup I was getting to decent adhesion with blue tape wiped with lacquer thinner.

Some of the issues were self inflicted as I was time splitting between house / yard projects, this and several other things. At times I hit my multi-tasking limits.

So now I am adjusting settings and printing parts. First successful test cube is below.

Snot string was due to still having the print head too hot due to poor contact with the thermistor.

Finished test cube. Size is now dead on.  This was with 0.35mm layer height, 60mm/s internal speed 30mm/s perimeters.

Now starting printer parts. Here is the back of the case for the display being printed.

 

The Repetier control software is great. It is much better than truing to control the printer directly via the twisty-turny knob on the  display.  Overall, I am rally impressed with the open source software (Marlin and Repetier) of this project.

Completed back panel for the display:

 

3D printer progress – assembly and test

At this point the frame is largely assembled. The carriages are mounted, the heated bed is installed and things actually move (at least manually).

I used a MK2A 300x300mmaluminum heatbed and had to move the motor motor and leadscrew mounts. The motors need to move out from the back as well. This is a good thing as otherwise the motor move would interfere with the 3×3 triangles. Flipping them over fixes that issue. However the smaller top 3×1 brackets do need to get trimmed for clearance. This was a quick trip to the band saw. .

The first piece to get moving is the bed elevation. The critical part of the motor alignment is at the bottom end. Need to get the motors under the drive screws. Sight along the frame to see that the screws are parallel to the legs in both directions and then tighten them down. The safety stops in the firmware need to be over-ridden as normally you can’t move the  axes to a negative position. In this case, negative is UP . So in Configuration.h make the changes as shown below to get the over-ride for testing and the homing directions:

// ENDSTOP SETTINGS:
// Sets direction of endstops when homing; 1=MAX, -1=MIN
#define X_HOME_DIR -1 // left
#define Y_HOME_DIR 1 // rear
#define Z_HOME_DIR -1 //top

You need to comment out the block below. It prevents the use of the max direction endstops. It took a while to find as I was troubleshooting why X&Z would home nicely but Y would not do any homing movement at all.

// Disable max endstops for compatibility with endstop checking routine
//#if defined(COREXY) && !defined(DISABLE_MAX_ENDSTOPS)
//#define DISABLE_MAX_ENDSTOPS
//#endif

#define min_software_endstops false // If true, axis won’t move to coordinates less than HOME_POS. — allow for testing
#define max_software_endstops false // If true, axis won’t move to coordinates greater than the defined lengths below.

This will allow moving the bed upwards under manual control.

I also made the initial settings for the stepper calibration. I am using 32 step microstepping (rather than the more typical 16), 8mm pitch threaded rod and a Micron EME cobra extruder. So the step calibration at this point looks like:

#define DEFAULT_AXIS_STEPS_PER_UNIT   {200,200,812,1168*2} // 32 microstep 16 tooth gears, 8mm acme rod & micron extruder

Belt installation was straightforward, but make sure to place a screwdriver blade behind the nuts for the clamp bars before inserting the screws. It is far to easy to push the nuts back and have them fall out as you attempt to clamp the belt to the carriage.

Currently all 3 axes are moving, and homing. Calibration still needs to be checked.

I was also configuring the temperature sensors to get the thermistor for the heated bed to work and get ready for print head testing. I am also running a thermocouple for the print head. I want to run thermocouples for the print head to use high temp plastics such as Nylon. The low output signal from a thermocouple requires an additional amplifier or special A to D convertor.  I had purchased the Max6675 thermocouple digital adapter. However, it turns out it is not compatible with having a 128×64 display!!! There are shared conflicting pins. NUTS!. Now I have to order some AD597 adapter analog boards (and wait for them to come form China, as I could not find any stocked in the US).

When I started the project I downloaded the Marlin software directly. I would have been better off starting with the package on the d-bot page (or at least using the configuration.h file). It was in a line by line comparison that I found the Y axis homing culprit. http://www.thingiverse.com/thing:1001065/#files   and select d_bot_marlin.zip