DIY Mini Taffy Machine – revisited 2016

So lately in 2016 (and quite a bit today) i’ve taken a look at revisiting my original DIY Taffy Pulling Machine from 2012. There was a lot of interest in the 2012 version, and i did try to provide enough information and detail in open source fashion for others to build their own, but i guess things just didn’t work out the best for that to happen.

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The biggest reason i revisited it is because it just didn’t quite feel finished, and quite frankly those big gears posed a pinching hazard. Plus many people didn’t know where to get their own. So in an effort to solve both problems in one i decided to make internal gears, but to do that successfully i had to shrink them down. In the process i decided it was time to make the gears 3D-printable thereby speeding up my own design process, but also opening up this design to a whole new set of people that otherwise would not be able to make one.

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I hereby am pleased to announce the re-releasing of my Mini Taffy Machine as an Open Source Hardware project. I have improved the CAD files and PDF assembly drawings with good blueprint title blocks (a skill i obtained from my recent machining courses this semester). So i hope you all enjoy and i look forward to seeing more of these in the wild and new iterations and modifications that people come up with!! (http://www.thingiverse.com/thing:1659568)

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Modding the Lulzbot Mini

So recently i’ve finally gotten my homemade / homebuilt Lulzbot mini working. And it’s working pretty good. The most critical problem i was facing was that my 3d printer would start printing either too close to the heat bed (or if i added extra bed leveling washers) it would print too far away. This was a critical problem as the first few layers are the most important and if you can’t get you prints to stick to your print bed then the rest of the print will usually unstick and fail. Thanks to some helpful people on the Lulzbot forum i was able to adjust my z-offset to the correct height that worked for me.

The second issue is that recently i’ve noticed my large and tall prints failing miserably at a certain height and the filament not coming out thick enough and the top gets all cob-weby like a spider web, but worse. Apparently this is called “Heat Creep”. The problem in part may be caused by the tiny blower fan on the Lulzbot mini not providing enough cooling and heat slowly rising in the hot end until the filament actually melts too soon and cannot be extruded properly. This makes sense as the problem only occurs after a long time printing. So the logical step was to replace the tiny blower fan (or squirrel fan) with a larger fan that will do the job. The new Taz 6 has obviously taken that tiny fan into consideration and has changed it to a large 40mm fan.

EDIT: The failing on large prints may be due to me using a half-size stepper instead of a full size stepper motor for the extruder. This means too much voltage is being applied to the motor and it is getting super hot. Over time this means the motor looses steps and probably causes my printing problems.

Unfortunately the Taz 6 x-carriage and modifications are not a drop in replacement for the Lulzbot Mini i decided to make my own. This is what i came up with and it seems to work beautifully. http://www.thingiverse.com/thing:1587110

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I have only tested this on HIPS so far, but it has eliminated the heat creep i was getting with HIPS. PLA apparently suffers more from heat creep problems than other filaments, but this mod will likely help with PLA heat creep issues as well.

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Homebuilt Lulzbot Mini First Prints!

Here are a few photos from my first test prints on my new, now functional (for the most part), DIY Lulzbot Mini that i made myself from scratch (minus the frame and electronics). All hardware assembly and electrical wiring were done by me. Phew. What a ride it’s been. The upside is i now now how this printer works inside and out. The downside it was more trouble that it was worth and i wish i had just bought one instead. lol. Whatever though.

 

Progress on my Homebuilt Lulzbot Mini

Today i made significant progress on building my own Lulzbot Mini 3D printer from scratch. Technically i now have two 3d printers i’m building from scratch, but the other one is bigger and one i’m designing myself. Just like me to not finish one project before starting another. At least i’m going to work on this one and finish it before continuing on my other one (which might be converted into a homemade CNC mill).

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Today was a major milestone because most of the components are put together and i finally was able to test part of the electronics i wired up myself. I was able to test the Y-axis motor and limit switches as well as the X-axis stepper motor. All seemed to function correctly using Lulzbot’s Cura software. The software did have an unexpected safety feature however, it wouldn’t let me turn any of the motors on without the bed thermistor wired up. So i had to wire up a temporary 10k thermistor for testing purposes. It worked great. I was running the Cura software under Ubuntu Linux. The Cura software gave me an error that it could not autodetect the serial port or something like that, so i ran it as the root super user and that fixed the problems.

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Since i’m building this thing from scratch instead of buying one premade i’m trying to find ways of cutting costs. Although i think i will end up spending more than i hoped. But anyway, part of that is looking into ways that i might be able to replace expensive commercial products like the IGUS bearings and the Leadscrew nut. I’ve already drafted up a 3d printable version of the leadscrew nut and posted it here on Thingiverse. The nut has yet to be tested, but i’ve also had some RJM-01-08 IGUS bearing replica prototypes made in Nylon. The RJM-01-08 IGUS replica bearings turned out to be too tight, but with a drill i was able to make them usable. They are currently being used to remove the wiggle and slop i was experiencing from using the 1mm too small LM8UU ball bearings.

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I originally got the LM8UU bearings as a cheaper alternative to the commercial RJM-01-08 IGUS stock bearings the Lulzbot mini uses thinking they would work. They work, and i am currently using some, but the stock STL files from Lulzbot have holes that are 1mm too big because of the slight size difference between them and the LM8UU. I might try to modify the STL files [i have modified the lulzbot solidworks files] to make LM8UU compatible parts in the near future, but for now i’m happy with my 3d printed nylon ones. I’ve heard PLA might work too, so i will experiment with that in the future as well.

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Here are some more pictures:

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Rediscovering 3d CAD because of 3D Printers

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This past week (maybe 2) I’ve been utterly obsessed with 3D printer stuff. It has gotten me excited about 3D drafting and CAD all over again. Simply because you can create a 3 dimensional object on a computer in a matter of minutes or hours and render it to look completely realistic, but now because of 3d printers you can actually make those objects (if you so wished)! Awesome!

Yesterday and Today I’ve been playing around with Solidworks again. My ancient 2007 version of solidworks. lol. But it works non-the-less. Although i’d love to try out Autodesk 123d Design (which is free). But, why oh why are there still no good CAD programs that run nativity on Linux. Especially if you have a Mac version. If it runs on Mac it can easily be ported to Linux. Why do you think the Arduinos and the rep-raps, and open-source, and so many other great things have taken over the world by storm? Yes it’s because they are great products, but also because they are cross-platform! Okay, End-Of-Rant.

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But Seriously, i actually really like designing something in CAD if it’s something i’m excited about. Today i ventured into the realm of something relatively simple, test tube racks. But sadly there are not currently very good designs for test tube racks available. Which actually surprised me. The three best places I look for pre-made CAD files are at 3dContentCentral, which is the oldest site of this kind that i ever encountered. It is mostly for people who use solidworks, but the great thing about the site is that it has a tool that can convert to and from many different CAD formats, including solidworks formats, IGES, STEP, STL, etc. The second is GrabCad. GrabCad is a new community also aimed at engineers sharing CAD models freely. It dosen’t have the nice file converter that 3dContentCentral has, but it has a vibrant community that provides feedback, help, and will check out your designs. Someone on GrabCad actually helped render the nice  looking wood rendering of my 1950s style test tube rack. How nice! Thank You! And the third is the famous MakerBot Thingiverse. Thingiverse is less focused on CAD formats and instead is focused on creative designs optimized for 3D printing. At minimum an STL file will be available for anyone to download and print on any 3d printer they have access to. I currently dont own my own 3d printer, but am currently using the Lulzbot mini that currently resides at my local library. How’s that for public access?!!

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So these are the three test tube racks i modeled today in Solidworks. Not super amazing i suppose, but i’m proud of them. My favorite is the nice wooden 1950s style test tube rack. I partly chose to start with that one because i have one that looks just like that looks like it was made by a monkey in china. It seriously is not as nice as my virtual one and not anywhere near as fancy looking either. But also because it is the standard test tube rack featured in the banned 1960s DIY chemistry book: The Golden Book of Chemistry Experiments. It was just begging to be brought into the modern world.

I then ventured into modeling a simple test tube rack because there were none available that i liked. I may make a smaller version of this one for 3d printers that have small print beds. Perhaps one with only 4 test tubes.

The last one i modeled after a nice round plastic test tube rack I’ve seen on the internet. I don’t have one, but I’ve been meaning to buy one. But i wanted to model one in Solidworks and create one that fit on a Lulzbot mini 6″ X 6″ print area that other people could print out too. So i made one of appropriate size and then made it able to split in two to be printed easily. I really like how the design came out. I hope to be able to test it out by printing my own sometime.

1950s Style Test Tube Rack:

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Economy Style Test Tube Rack:

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Round Mini Test Tube Rack:

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2nd batch of 3d printed parts!

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Today I tried printed out more 3d printed plastic from the library Lulzbot mini. I printed 3 more 90 degree corner brackets for my old 1″ extruded aluminum 80/20 brand t-slot that I originally bought to make a rep-rap 3d printer and/or CNC mill. I never finished it I might add. Perhaps I will pick that project up again. It would certainly fit my trend this year of finishing old abandoned projects (like my xyzzy motor controller).

I also printed two spacers from my solidworks files for my homemade taffy machine. (They came out great). And I tried my hand at making a copy of my own house key. They key didn’t print the best, and in addition did not fit in the doorknob for some unknown reason. 😦

The biggest accomplishment today was printing plastic copies of the 80/20 t-slot linear bearings. I still prefer the aluminum ones, but my low cost ABS plastic ones are much affordable and should work fine anyway! The ABS is actually some what slippery and does work by itself despite it not being great.

The plastic with Teflon (actually HDPE) tabs screwed on works just as nicely as the aluminum ones do. I think I will print more (and bigger ones) in the near future. These should help greatly in turning this into a giant 3d printer!

First 3d printed parts!

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I printed my first 3d printed parts on Saturday. I used a publicly available Lulzbot mini. The gears turned out great. The software was extremely easy to use. Just click and print, quite literally. The open source Cura software was just beautiful. The lulzbot mini has consistently been critics top 3d printer for being the easiest to set up and use. And I can see why.