Back, RDR, X-axis and Solidworks

In the past few months I have discovered that there are a few things that are very bad for progress on building a RepRap:

1. Moving house.

2. Changing Job.

3. Red Dead Redemption.

Having completed the above three I am now back building my reprap. I have almost finished the x-axis. See the below photo of my progress. Struggling to find time for the build at the moment so progress is likely to be slow for a while. Drilling and shaping the cast plastic bits is becoming quite annoying, wish I had held out and bought proper printed parts, never mind hind sight is 20:20!

From Mendel

I have also been practising using Solidworks at work, so what better to tune my skills than with the Mendel Solidworks files. See below for some videos I made using Solidworks. I have changed the model quite a bit, fixing a few errors and making the limits rights so you can only move the axes to the allowable positions. I will try and post my adjusted assembly files soon for those who are interested.

Sketch it Up

Just thought I would write a few words about using SketchUp for modelling with RepRap. I'm not sure if it's just me but very few people seem to be using SketchUp for doing their designs for the project. I really like Google's SketchUp and think it is fantastically easy to use. Capo's recent comment reminded me of the fantastic model he put together of Mendel and prompted me to have a play again myself. A quick look at Capo's blog and you can see how he has used SketchUp in a number of ways for both presenting idea's and for component design.

The below video shows Capo's model that I have coloured then animated.

Link to the SketchUp Mendel Model by Capo:
http://sketchup.google.com/3dwarehouse/details?mid=86dc5e3cc80958355ad914839c51e370

Link to Capo's Blog
http://capolight.wordpress.com/

Geared Extruder and X Carriage

I've done some more work on the extruder build. I had some problems getting the gears to mesh correctly, I found that the large gear seemed to be slightly ovalised which meant that as it turned the wheel would grind in some places and miss in others. I think I have solved this by filing down the teeth that were grinding using a triangular file (note the red marks I have put on so I know where to file) until eventually the gear wheel was circular. It's still not perfect but should be workable I think. I still need to glue the nozzle assembly in place.





I have also starting working on the x-axis. Beginning with the x-carriage. Nothing too difficult here except the captive nuts. A few of the nut locations had to be drilled to the correct shape to hold the nut, I did this using my dremmel clone with a small drill bit and file attachments, time consuming but works in the end. It is also important to remember which holes have to be drilled at an angle.

Adrian's Geared Extruder Build Part 1

The RP parts I have are for Adrian's geared extruder see the wiki here. For this you need some pats not listed on the original BOM list. There are a couple of different screws you need, nothing hard to find on ebay. Main parts you need are a short piece of M4 threaded rod. An M4 "Insert" - this is a splined piece used to grip the plastic filament. An M4 wing nut, and 3 bearings. The splined piece I got from ebay here is a bit different to the one shown in the wiki but serves the same purpose. It doesn't have a grub screw but it is internally threaded so should stay in place with bolts either side of it. It was listed as "Ripmax DYCO M4 x 0.7mm Coupling Insert" looks like it is used in the clutch mechanisms of model cars, trains etc.
After a bit of drilling and shaping the parts seem to fit together ok.

Belt Splitting

First thing I thought I would try out of my plastic parts was the belt splitting jig. I managed to drill the holes ok. The slot was a little trickier, I used my dremmel clone to do this. A tip I have found for drilling the holes in the plastic if you are concerned about it "biting" into the plastic and cracking it is to run the drill in reverse and it tends not to grab at the plastic, but takes longer to drill the hole. Below you can see the finished jig. It worked perfectly and I now have the belts split successfully.

Plastic RP Parts Here!

I now have my plastic parts. I finally went for a set of the cast or moulded parts being sold by fotonlabs on ebay for about £150. I decided it was worth the saving and do the drilling myself (I hope). The seller warned me that they had some breakages reported from the postage, and that they would replace any parts that were broken. They were right, a few parts did arrive broken, but they have been very good and are sending replacements out straight away. The plastic is quite brittle, and the seller has told me they are changing the plastic mix to be more flexible. I have had a go at drilling a few parts, and the seem to drill pretty well but I think as the plastic is quite brittle I will have to take care and not rush it.

I will be moving to a new house and job in a month, this might get in the way of making quick progress but I should still find an hour or two here and there.

Hot End Test

I decided to have a go at extruding some plastic through the hot end to make sure the temperature I was reading was correct. I used the ramp button to slowly get the hot end up to temperature. Everything went well, at about 160 to 170°C I could start to smell the PLA melting, smelled a bit like burnt sugar. Once it got up to 190°C I had a go at pushing the plastic through, it took some force, but it definitely worked, I can see why people are having problems with the brass nozzles coming out. Everything seems to work so far, woo! Check out the screenshot and video below.