3D Printing – Borderlands Sniper Rifle – Part 3

Quite a big update this week – the scope and rail are, bar more sanding and finishing, essentially complete.

The scope itself is made up of 6 individual parts – for ease of painting, I’m not attaching the front to the body yet as it has quite a significant overhang which will be impossible to get under if I glued all this together.  The above photo is everything just resting together.

I made a few adjustments to the model before I chopped it up for printing – I hollowed it out, so you can see through it from one end to the other.  My reasoning for this was that it would a) give me the ability to see through it, you know, like a scope, and b) it would be lighter and use less filament than if I printed it as a set of solid parts.  That said, I had to add some hidden features to help me with sticking it all together once it was printed.

Between the rear fluted part and the first part of the central tube, I indented the flutes into the body by about 2mm, so that I could press one into the other, which makes sure everything is lined up properly.  In the ends of all the other pieces, I cut 2mm diameter holes to a depth of about 15mm, which I figured I would be able to insert a clipped down cocktail stick to give the joint extra support, and also keep things nicely aligned.

While this seemed like a good idea at the time, due to me not taking into account the small tolerance of the final prints, the holes ended up being slightly smaller than the diameter of a cocktail stick, which led to me having to not only clip the sticks down to fit, but also file them down to get the diameter small enough to fit in the holes.  *note to self: remember the tolerance*.  Once I’d done that though, the parts stuck together perfectly, with very little gap.  I used a little filler to hide the joint completely and sanded everything down while the front section of the scope was printing.

I stuck the three parts of the front of the scope together in the same fashion, and then went to join the two parts together.  This is when another fundamental error on my part became apparent:  All the centre parts had six holes cut into them in the same locations all the way along, which meant that they could fit together at only six possible orientations.  With the cylindrical centre sections this was fine as it didn’t matter which way around the parts went together as the profile was the same all the way along.  The issue arose because the rear most part with the flutes could be fitted into its socket in ten different orientations, and because it had the side parts with the screws and the sight on top, it has a ‘correct’ way up, as does the front section as it has the scope cover and the front sight, which has got to line up with the rear one.  It turns out that in my haste to stick this all together (because I’m impatient…) I’d mounted the rear part a couple of orientations off from the rest of the piece, so that the holes in the front section didn’t match the holes in the end of the rest of the scope.  I could have just glued the parts together, but there was no easy way of ensuring that it was lined up completely right, and there really wasn’t much surface for the glue to get a good purchase on.  The solution I came up with was to print a small cylindrical tube part that I could slide into the end of one half of the scope and glue into place, and then attach the front part of the scope to that.  I named this part the ‘idiot joint’ in my honour.

The idiot joint in all its glory.

Around this time I also printed the attachment mounts in a couple of parts so the scope could sit in them and the top then placed over and glued in place when I am finally happy with the finish.

The next part to print was the rail.  For some reason, and I must have been tired, I decided that the best way to print this was to cut it up into sections no longer than 150mm (the tallest thing I can print in the printer, give or take) and print all the pieces standing up.  I decided to use the same method as with the rest of the scope to join them, e.g. cocktail stick supports, and this time made the holes a tiny bit larger so I wouldn’t have to file the damn things down again.

The massive disadvantage to printing them this way, other than the fact that if the head hits them too hard they could fall over, is that the grain of the print is essentially going across the part rather than along it, which means they are rather easy to snap in half, or in thirds, or quarters, especially if it doesn’t print properly in a couple of places…  In addition to this, because I’d forgotten to switch off support generation, it printed support material inside the holes at the ends closest to the print bed, to support the end of the hole.  Which proved almost impossible to remove.  After much swearing and snapping two pieces, I had to print a couple of bits again, which I this time printed laying flat on the bed, with no supports, which gave a much nicer finish and a stronger part overall.  I’m not going to reprint the rest of the rail as the remaining parts seem to be holding together pretty well.

I’ve learned quite a lot about what not to do and what to keep an eye on when modelling for 3D printing this week, and it also marks the point at which this project is going to be going on (certainly fabrication-wise) hold for the moment. – – Filament is at an all time low and I’ve got some other projects I’ve got to use it for, so I’m just going to concentrate on working out how I’m going to get the electronic functionality that I want and how I’m going to print the remainder of the rifle without using all the filament in the northern hemisphere.

More soon!

Part 1Part 2

3D Printing – Borderlands Sniper Rifle – Part 2

When last we met, I’d just started printing a test print of the rifle handle to see whether it was the right size for my hand.  As the rest of the rifle can be scaled universally, getting this piece the right size would impact the size of the rest of the model.  Below are the results of that test print:

Even though the handle was pretty close, I feel it could be a tiny bit larger, so I’ve increased the size of the model by 3%.  Doing a little measuring within Fusion 360, it turns out that when this entire thing is built it will be over 1.5 metres long!  One thing I was impressed by was how smoothly the model printed – this was my first time using the Simplify3D slicer and it is very good indeed.  I’ve also decided to print the trigger as a separate part for a few different reasons, the main one being that I want to be able to move it, and a secondary one being that the support tower wobbled while it was printing which led to a wobbly print.

After a couple of other tweaks to the model, I decided to start cutting things apart ready for printing.  When something is 3D printed, the software adds support structures so the hot end doesn’t have to end up printing in thin air.  While these supports are generally very good, they can leave little blips or marks on the model where they attach.  With that in mind, I wanted to ensure that I could print as much of the rifle as possible without having to rely on supports.   The part I started with was the calibration dials on the scope – this was a relatively straightforward object, but due to the orientation of some parts of it, I needed to break it apart to print it in a total of 8 separate pieces.

My aim was to have the dial parts the caps slide over the rod I’d added to their bases.  The main body was split in two as it would have to encompass the body of the scope, which would be printed separately.  Technically this worked, although I didn’t allow enough clearance around the rod on the side dial, so I had to snap that off to get the parts to fit.  I didn’t bother to sand or finish this part as I was just testing whether I could get it to fit together properly.  Here’s a couple of pictures of it all stuck together:

I’m going to adjust the model slightly to allow for more clearance on the side parts, as I’d like to be able to have the dials be able to be rotated if possible.  I’ll also do all the sanding, filling and other finishing before I glued it together!

The next part I have printed is the sight.  I wanted to be able to add a piece of clear acrylic with a design printed on it to the middle of the sight, so I had to cut the model up accordingly.  Below are the final parts, which have been filled, sanded and filler primer-ed.  They need to be sanded again and I may have to add some more filler in certain areas too.  I cut the piece of acrylic from a small 3mm sheet that I picked up from Hobbycraft.  The arrow indicates the top as it’s not quite square.  I’ve press-fitted it together in these photos as I’ve still got quite a lot of finishing to do…

More soon!

Part 1 – Part 3

3D Printing – Borderlands Sniper Rifle – Part 1

As some of you may know, I am rather a big fan of the Borderlands games, and I’ve long coveted the idea of making my own version of one of the sniper rifles from the game and now that I have a 3D printer, it seemed like as good a time as any.

Rather than go with something small and simply shaped, which would, you know, be sensible, I’ve gone for this: the Barking Volcano.

I chose this one for three reasons:

  1. It looks cool.
  2. It will give me a serious modelling challenge.
  3. My character already had it so I didn’t need to go looking for another rifle.

I took a bunch of screenshots to use as reference material and jumped into another complete unknown – Autodesk Fusion 360.  Fusion 360 is a CAD/CAM package which operates somewhat differently from the 3D software that I’m used to.  After watching a few tutorials online, I felt I was ready to jump in and start modelling.  Using the side view of the rifle as a canvas, I started with the scope, and the stock and once those were done, moved on to the more complicated shape of the body and handle.

Overall the modelling took about 6-8 hours over a number of days, with quite a few false starts and no small amount of swearing.  I’m pretty happy with the final result.

To make sure that I’d got everything scaled properly, I decided to do a test print of just the handle, as the size of the rifle depends on the size of the handle.

I exported just the handle to Simplify3D and set it up to print.  Results to follow… (part 2 – Part 3)