Getting the Printer up and running again.

I have now got the 3-D printer up and running again and will discuss some of the maintenance I carried out on it.

Firstly I attended to the wiring, checking all the connectors on the central processing unit and in some cases reworking the connections to prevent errors such as oscillating stepper motors which the machine has suffered from. The thermostats on the printheads then needed reglueing in the correct position, with high temperature glue, so after calibration, they now read the temperature of the Hotends very accurately. 

I then brought each print head up to operating temperature, 200° C, to clean the inner channels from the buildup of plastic and any carbon residue. The primary printhead which has become blocked with carbonised denatured nylon is proving very difficult to clean out and will require the full disassembly of the head, in the meantime I am going to use the secondary head to print with. This is not an easy change over and I will have a blog entry explaining how I achieve this. 

Finally I then checked all the moving components were well lubricated, tightened the belts which control the X and Y movement and tightened the Allan screws to prevent any vibration during operation. 

I then moved to fine calibration. 

Projects.

I have several projects that I am looking forward to getting my teeth into and getting the 3-D printer up and running again. Firstly I've got a lot of work to do on the printer maintenance wise, during the technology projects I jammed up the primary printer head with nylon which I think has denatured and carbonising formed a solid block inside the head. After cleaning that out, some of the wiring around the printheads has become loose which needs attention to have reliable printing. Then I'm going to work on maximising the precision of the 3-D printer aiming for 40 µm resolution and 0.05 mm layer thickness, using a series of complex test prints with peculiar curved shapes and high detail to really push the performance of the printer. To give a comparison the Makerbot replicator, a commercial product, has a precision of 100 µm, which I am aiming to surpass. 

I have another few smaller projects I didn't quite finish over Christmas which I'm going to work on before starting some big projects which I've been looking forward to for a long time. 

The first project is to enter some of the Makerbot STEAM (Science, Technology, Engineering, Art and Maths) challenges. You can check them out here: http://www.thingiverse.com/challenges/  I will have future blog posts showing my entries. 

The next project is to build a 3-D scanner. I backed a 3-D scanning project on Kickstarter called Atlas 3-D. It was successfully funded in February and I am looking forward to the delivery of the electrical components sometime in July to build the scanner. The parts include the stepper motor, wiring and lasers and then I will use a Rasberry Pi and Rasberry Pi camera and print of the other components to assemble a DIY style Open source 3-D scanner. The 3-D scanner will run on Open source software, which I have been following the development of, called FreeLSS. (https://github.com/hairu/freelss)

I then will be designing and 3-D printing a range of small models of classic commercial vehicles, in 1/50 scale. I have collected vintage vehicle models for some years and I am going to develop my own models of vehicles and trailers which are not available as commercial models. 

So it's going to be a busy summer holidays.

Long time no printing.

 I have been somewhat plagued with ill-health and exams so have been unable to carry out any 3-D printing  related  projects. Struggling with  arthritis it  is going to be very difficult for me to work on all the projects I planned to complete this summer however I will fight on.  Typing is very difficult however I am now making use of the dictating feature on the iPad so I can still complete my blog posts.  I have completed my A-level technology project and will write a post about it and then have a series of projects I am looking forward to working on over the coming months.

Oscillating Material Feed Stepper Motor

My 3D Printer has suffered from Oscillating Stepper Motor which although rare seems to have occurred to other RepRap style Printers; when the stepper motor which feeds the material into the Print Head repeatedly changes direction, causing no overall movement of material, and preventing printing. At first, I thought this could be a loose connection in the mother board and general circuitry of the 3D Printer, but after checking all the wiring and connectors, this was eliminated. I then though it was a software issue, sending a corrupted signal. However, after great research I am still unsure about the root of the problem. One option, which I was reluctant to follow, was to reformat the 3D Printers software. Another idea, because my Printer is a dual extrusion model, with two Print Heads, thus two feed motors, was to swap the connections, so that the second motor would take the first motors command and feed into the fist extruder. Although a short term fix, it worked; so the problem isn't software related but must be in the stepper motor, or its wiring. Before progressing any further I will contact the manufacture, to enquire, and potentially get a replacement stepper motor, to solve the issue. Up un to now, I have had very little hassle with the general running of the 3D Printer and it has enabled me to develop my CAD/CAM skills, especially in design preparation for additive layer manufacture.

I have experienced this problem again today (02/07/2015), this time both stepper motors oscillating instead of rotating when sending the manual command to extrude 5mm of plastic. I fixed the problem by removing the stepper motor connections from the circuit board of the printer and then reconnecting them, checking for any loose connections.

3D Printer Hotend fix.

I experienced quite a catastrophic printer failure today, when the temperature of the Hotend (the component which the plastic filament passes to become molten before extrusion) raised rapidly to 250°+ causing the carbonisation of the PLA material. After quickly shutting the printer down, and increasing ventilation to clear the burnt plastic smell I investigated the cause of the failure. The thermostat had disconnected from the main heatsink of the Hotend, which meant that it was heavily under-reading.

After some research, and much thought, I worked out a process to reaffix the thermostat to the hotness. Simply glueing the thermostat back onto the Hotend, could potentially effect the sensitivity of device, and was the original fixing method. (Which evidently failed) Therefore, I decided to use wire to tie the thermostat to the Hotend positioning it onto the heatsink, providing maximum temperature accuracy. Only a small job, but without accurate temperature control, successful prating is almost impossible. I considered the effects of heat conduction though the wire tie, but decided that this would be insignificant and would not cause any harm to the cables as they all have heat resistant outer covering.

I attach two images of the Hotend in my printer, with the wire fixing holding the thermostat in place.

Disassembly of the PrintHead, notice the thermostat
and circuitry (on LH Hotend) disconnected from the Hotend.

The insulated cabling tied to the Hotend, holding the
thermostat onto the Heatsink for optimal reading accuracy

A- Level Tech Project

My A2 A-Level Technology project is a Sound Multicore Cable Reel. I have made extensive use of 3D modelling software throughout my project, in the design, development, and modelling stages. I have found making 3D Printed models a very powerful way of connection the cient with there developing design.

A selection of the models I made during the development process.

Lancia Statos

Just for fun and to experiment with new materials I have decided to make a model Lancia Stratos Rally Car using the designs published by Makerbot. 

First components for the Stratos

I would like to use ABS for the main body, and this will be a challenge as it is a difficult material to print. ABS doesn't adhere at all to Blue tape, like I have used successfully with PLA, or the glass bed and is generally just hard work to print with. So much so that it is becoming increasingly unpopular in the 3D Printing world, with most manufactures saying their printers are "not optimised for ABS" (i.e. the prints lift off the bed). Comparing the cost of PLA and ABS material on eBay, for example, also shows which one is more popular. Although it has been a race to the bottom with both plastics, with the prices rapidly dropping with the expansion of the industry; the price of PLA has plateaued, whilst ABS continues to drop, and at present is about £10 cheaper then PLA.

For the few die hard 3D Printers who fight with ABS, the method seems to use a heated bed at a scorching 100-110°C. Although, I have seen the use of water soluble glues, Cubify use this method with their printers. However, getting a consistent adhesion isn't easy, and the base of the prints have a less then desirable finish/texture. I have a few ideas of my own to improve ABS printing, and will post about them later.