Z axis upgrade

3D printing as a hobby brings with it plenty of tinkering. I noticed an effect in my printed parts that looks like z wobble from my old cupcake, but the openbeam printer should be better constrained in the xy axes to prevent that. Basically there are 8mm guide shafts that keep everything aligned and a pair of z motors with misalignment couplings and a threaded rod and M8 nut to actually impart the force in the z direction with minimal x and you components. I had used some spare M8 threaded rods that I bought from makerbot when they were clearing out old cupcake parts. What I noticed was that the ridges on my parts changed size as a function of layer height. This meant that some layers were being squished more than others. The pattern was the exact same pitch as the threaded rod, which meant the z didn’t […]

Read more

First long unattended print on openbeam printer

In preparation for 3d printerfest at Einsteins workshop in Burlington, I attempted a 6+ hour print, which is by far the longest I have done, unattended or otherwise. My previous printer simply wasn’t large or reliable enough to print for 6 hours. This print is a 150 mm diameter herringbone gear bearing. I came home from work expecting a big mess and actually was surprised it worked. It’s a bit thin in spots and didn’t break free, but it’s pretty close. I think I just need to make the cold end of the extruder a tad more reliable. I’m pretty excited about my new larger build area, and think I can get quite a bit better results than the previous printer. Next up, upgrading this to octopi as well.

Read more

Octopi on the makerbot

Problem: Running my makerbot over serial can be problematic because I have an aged laptop. I’m still using an old laptop I scavenged when IT was giving away tired machines. It has a Core 2 Duo at 2Ghz, a 40GB hard drive and 3GB RAM (32 bit OS). It’s still kicking, and can usually do what I need without too much hassle. Recently though, The act of switching windows during a print caused the serial buffer to run out, and the printer would sit for 30 seconds oozing while it waited for more data. Solution: Enter OctoPrint. I recently got a Raspberry Pi model B for a larger PCB design project I was planning, but that is temporarily on hold. I did some reading about what I could do with it, and was torn between a pandora interface for the stereo downstairs, and a mini-host for the 3D printer. Once […]

Read more

You just got a 3D printer – now what?

With the holiday season upon us, and the availability of 3D printers increasing, we have reached the year that many people will be getting or building a 3D printer and then wondering what they can do. There are two main ways to get things for your printer to print – you can download them or you can design them. Downloads There are quite a few sites now that host 3D printable models. The first major one is Thingiverse, which is owned by Makerbot (who is owned by Stratasys). Thingiverse had files for 3D priting and for laser cutting. Some models are extremely well made, and print with ease. Other things may not be well designed or could even be impossible to print. A good rule is that if there isn’t a picture of a printed part on the thing’s page, then it’s probably not printable. Also make sure that the printed […]

Read more

New electronics for the makerbot part 2

Here is my makerbot electronics as of Friday. Including the relay board, there are 7 boards involved in running the bot. I finished soldering the proto board to connect my Pro Mega to the Quadstep Friday night. I got everything torn off and installed my new board stack in place. Still some work to do for making it look nice, but it’s already a big improvement. Moving on to the software side, I had a heck of a time getting anything to load from the Arduino environment. After nearly 8 hours of debugging and finally loading the basic blink program via the AVR Isp port (which involved teaching the Arduino environment that my pololu AVR programmer is like an stk500v2), I discovered what was happening. It was toggling the blink Led every 2 seconds instead of 1! I triple checked the fuse settings against various AVR calculators and they were […]

Read more

3D Printer update

I’ve finally started getting back into printing. I had a bunch of filament feed issues, and it was a combination of a loose hobbed gear, and the set screw part of one of the extruder drive gears started to fail. Fortunately, I had enough stability left to print a few spares (in addition to the 4 I had in reserve, just in case). I got everything going again, printed a few things, and was printing during the scope repair. Then this: This was a new failure mode, but not completely unexpected. I’m not certain if it was just a bad gear, or if the Skin plugin I was experimenting with was causing the gear to be loaded more than usual. The automatic extruder fan seems to be working though. I’ll video it next time I have the printer repaired.  

Read more

Extruder fan controller

I brought my makerbot to the Reading Friends and Family Day to show at the Reading Robockets booth. I’ve been having some issues with the extruder skipping, and I think part of the problem is that the stepper motor that does the extrusion is overheating a little. MIT Swapfest was also this past weekend, and I got a number of small useful items, like a few of these fans for $1 each (including the finger guard). these fans are LOUD and move a lot of air.   One thing that I liked about the fans is that they are the four wire variety which means they can have speed controlled with a PWM signal applied to the blue wire. The base frequency is around 25 kHz, and the duty cycle controls speed (from 30% to 100%). I did a bit of research online, and came across a neat ieda for […]

Read more