User:Lmartin iii/Project 1: Printhead Changer

Week1 Narrative
This particular project is directly related to the course instructor, as it is his 3D printer that we are working with. After conversations with him we were made aware of the functional difficulties of changing from one printhead to another, on this particular printer. A process that involved removing and reconnecting multiple screws, and several electrical connections at the circuit board. Four to be exact. Connections for the stepper motor, fan, extruder nozzle, and thermistor... quite a cumbersome process. The objective of this Printhead Changer Project is to create a system that would allow you to quickly, and precisely, change between printheads.

After brainstorming and discussions with the team it was determined that I would initially focus on research of existing solutions to generate ideas, and things/materials that could be used to accomplish the task. Since Jamie was learning how to use the laser cutter, my first research focused on finding a suitable material to make whatever we designed, on the laser cutter. I figured whatever was used needed to be rigid. I learned that some materials should never be cut on a laser cutter (Like: PVC, vinyl, pleather, artificial leather, thick ( > 1mm) polycarbonate/lexan, ABS, HDPE/milk bottle plastic, polystyrene foam, polypropylene foam, fiberglass, and coated carbon fiber). The materials that do work well, that I thought might work for this project are: cork, acrylic/lucite/plexiglass/PMMA, Delrin (POM), Mylar, Teflon, and Carbon Fiber mats (that have not been coated with epoxy). My next step was to further research the materials that could work. I began finding information on Cork. It had some good properties, but the maximum thickness that the laser cutter could cut is 1/4", and my greatest concern was its rigidity at the thickness we needed. I found a website that sold semi-rigid sheets of cork and blocks of cork in various sizes. This could have been a resource for obtaining the material we need.

Once I was able to see and get my hands on the 3D printer we were creating this Quick Change for, I realized that it would be easier, and more cost effective, to create the new part in a 3D software and print it, as opposed to making it on a laser cutter. I suggested we refocus our energy into designing possible solutions. I took pictures and detailed measurements of the part(s) of the printer we were designing for.

In discussions with the team about design I mentioned the changing process should be as simple as possible. Ideally, something that could be done in 2 to 3 steps, with precision (being able to align it exactly where the previous head was), being of utmost importance. In our team discussions about design we also dealt with wiring. I noticed there were wires coming off the motor, the fan, and the nozzle (10 wires total) all going in different directions to the circuit board. I suggested grouping them, and running them all the same way to the board. Then splicing them, and adding a plug system closer to the printhead so it could easily be connected and disconnected without going to the circuit board.

Since this was all still very early in the design process, we were all tasked with researching design ideas and to begin formulating possible solutions for the quick changer that we could compare and collaborate on, make a decision, then move forward to the next phase of design.

Week2 Narrative
During week two I began researching quick change options that have been successful in other applications. I actually found a blog that featured a 3-way Quick-fit Extruder, that fit into the Quick-fit X Carriage and locked down. What was important for our project was the fact that it had a universal adapter that you could attach various printheads to, slip it into a base, then turn a latch to secure it in place. I figured this would be the basis for my design. I set out to find a suitable latch to use in the design. I found a latch on a DeWalt tool case of mine.

This particular latch is larger than what is needed for our application, but I photographed it, and took a video of how it operates. I detached it, brought it to class and showed my team members so they could have an idea of what I was thinking. I also made a trip to Home Depot, Michael's, and Lowes this week to find a similar, smaller latch that could be used. Home Depot and Michael's didn't have any options, but what I did find at Home Depot was a different latch system that I would explore in design. The beauty of this is that it was also something that could be designed and printed on a 3D printer, potentially eliminating the need to buy materials. At Lowes I found a smaller latch, that I purchased, just in case.

This week the instructor brought in another printhead (a paste extruder), that we found to be much larger than the existing extruder. It couldn't fit on the existing base. This is something that had to be considered when designing. We need to be able to take printheads of different sizes, attach them to a universal adapter, and connect them to a base plate. I began sketching design Ideas based on the measurements I took of the printhead(s) and other components. I emailed Jamie a copy of my measurements so he, too, could work on the design. I sketched an adapter plate that any printhead would attach to by screws. I also sketched a larger base plate with a slot on the right for the adapter to slide into, and on the left a latch would swing up and lock it down.

I then created a to-scale, cardboard mock-up of my design so my teammates could visualize my ideas.

Overall, the team was receptive of my design, with modifications based on Jamie's feedback and input from the class. Using a 3D software to create the design is my next task. For Jamie and Sergey, we decided that they would focus on the electrical portion of the project.

Design Inspiration:

http://richrap.blogspot.com/2012/08/3-way-quick-fit-extruder-and-colour.html

http://richrap.blogspot.co.uk/2012/06/mini-quick-fit-huxley-sized-extruder.html

http://www.youtube.com/watch?v=ffICsLWzn2o#t=39

http://www.thingiverse.com/make:41931

Week3 Narrative
During this week I focused on creating 3D models of the Quick Change base and adapter using Solid Edge. Since Solid Edge was the program I familiarized myself with during Project 0, I though it would be the best application to use to accomplish this task. I was able to create a rectangle that I intended to modify and make into the base. I learned how to convert the measurement system from inches to millimeters. I also learned how to use layers, which is helpful for turning on and off parts of the model as needed. I experienced a lot of trial and error with this application. Overall, I felt it was taking a really long time to do what I had in mind to do with the model. Based on what I had seen and heard in class about SketchUp, I decided to see if it was a better/easier option to work with. I searched the internet for user reviews and to see if it was compatible with my computer, a Mac. It got pretty good reviews, and thankfully, it is compatible with Mac. I downloaded and installed the software. I viewed an introductory tutorial, which was very straight forward. I opened the program and began familiarizing myself with each of the tools. I created and modified a random object using each of the tools. I felt the learning curve wasn't as steep as it is with Solid Edge. I concluded that it was worthwhile for me to start over creating the models using SketchUp. I started the model of the Quick Change base. I was able to incorporate the holes for the extruder nozzle, and attachment screws.

I also searched for what was needed to print to the MakerBot. I learned that I needed MakerWare. It is also compatible with Mac, so I downloaded and installed it too. I viewed a video on "How To Use MakerWare." It's a simple program that allows you to import .stl, .obj, and .thing files to organize and prepare for 3D printing. I practiced using the different tools in the program, which I felt was fairly easy. Completing the 3D models and printing them are my next objectives. My teammate(s) is tasked with pushing along the electrical portion.

Learning Tools:

http://www.sketchup.com/learn

http://www.makerbot.com/support/makerware/documentation/usage/

Week4 Narrative
During this week I continued to work on the modeling in SketchUp. I was able to complete the model of the base.

As I was nearing completion of the adapter plate, I was having trouble putting in holes for screw placement. With Ben's help I realized that all of my measurements, on both models, were off by 10%. They were drawn in mm as opposed to cm, so I scaled them both up by 10. I was then able to place the screw holes. I also had to download the .STL extension for SketchUp so I could export .stl files that I could open in MakerWare. I exported .stl files of the base and adapter plate, opened them in MakerWare, and arranged them for printing. Since Ben seems to be the resident expert on printing to the MakerBot, I asked him to check over my file before I saved it to print. He suggested I make a couple structural changes to aid in a successful print job.

I made the modifications to the Quick Change base, re-exported the .stl, opened and arranged it in MakerWare, then saved the .x3g file to an SD card to print. Once the printing began I waited around to make sure it started correctly. Good thing I did, because it only began to print half of the Quick Change base and the Quick Change adapter. I let the printer go until it was 12 - 15% complete before canceling the print job. I did a google search to try and find out what might have caused my printing problem. I eventually wrote an email to MakerBot Industries Support. They responded with some suggestions to try to make sure my model file was good for printing. I uploaded my base .stl file to Netfabb Cloud Service. This service examined the file and repaired all imperfections in the file. It then saved the file and sent me an email with a link where I could download the fixed file. I prepped the fixed file for printing with the adapter plate.

Resource(s):

http://www.makerbot.com/support/replicator2X/troubleshooting/

http://cloud.netfabb.com