Roll Top Pencil Case + Bonus 3D Print

In the UK it is the summer holiday break for schools and I thought I would take this time to make something for some family friends young son.

I was trying to think of something and the idea of a Roll Top Pencil Case came up, I have seen a Roll top case cut out on a laser machine but I had not seen a 3D printed version, I wondered why that would be, would it be the roll top?

Anyway that's how the idea came up, and so I set out on my journey of trying to make a roll top pencil case.

Fusion 360

3D Printer

PLA Filament

CA Glue or similar.

Cocktail or toothpick to apply the glue.

As with most of my ideas, the design comes straight from my head, a lot of people will do a sketch or something to design from, I'm a more of a make it up as you go along type of person, which can have it's downfalls, going backwards and forwards with sketches etc but get there in the end.

First and foremost I wanted a design which was easy to assemble

So with the basic format in my head and some dimensions, I set off on the Roll Top pencil case journey.

The first thing to do was new component and start a sketch on the top plane, a rectangular shape was sketched and I used the fillet tool at this point to sketch in the radius to each corner to what looked a pencil case, with this done I extruded to 3mm bearing in mind the depth needed for the runners for the roll top.

I used the line tool and 3 point arc tool to create the runner guides for the roll top assembly to what looked liked a good radius for the roll top to run around, and made the space for the roll top at 2mm I concentrated on just one side of the pencil case assembly and then I would mirror the assembly of the center plane to create a body, I had completely forgot at this point that the pencil case would need a base/floor so to speak, or the pencils etc would be laid on top of the roller, so following the path of the roll top guides I sketched in the base with a curved back to follow the roll top path.

I'm thinking at this point should I make the case in 2 halves and glue together, anyway, but I went away from that idea and ended up extruding the base of the case the full width of the case, I mirrored the initial side first to the width I wanted, then extruded the base and cut this into the mirrored side using the combine tool, was running before I could walk at this point as I hadn't tried to model a roll top, but with the main body completed in 2 sections we could move on.

Onto the roll top next.

Ok this is where the fun starts as I have no idea at this point if a 3D printed roll top would even work.

I set out with the dimensions I had for the width taken from the roll top guides and I would off set this each side to -0.3 mm this should give enough clearance for the roll top to run smoothly.

I sketched a rectangle shape the length of what looked liked the length I would need for the roll top to slide open fully, I have no idea how to measure this using the existing roll top guides so it was guesswork at this point, and also if I projected and extruded from the roller top guide I would have to print the roll top vertically which I didn't want to do, I extruded this to 2mm

I then sketched from the top surface 2 rectangles to each edge the same width of the roll top guides + 0.2mm for clearance, and extruded this - 0.2mm this would ensure that the roll top would glide smoothly along the runner guides.

I could now go onto creating the actual flexible roll top, I would leave a gap at one end for a knob to open an close the roller and from then on there would be increments of 0.5mm I created a rectangle shape of the top face 12mm in from the end and extruded this to a point where I thought it would give enough flex without breaking, this was a another guess, I then used the rectangular pattern tool to create more of the same along the length of the roll top.

The next job was to create a knob to open and close the roller top, initially a 10mm x 5mm rectangle was cut out and extruded fully, then using the same face to sketch from I projected the rectangle and extruded to the thickness of the roll top and created a new body, I then sketched for the surface of the new body to create a knob and extruded that upwards 8mm and joined this, I created slots either side of the knob and filleted.

The next job was to create a surround for the Roll top case, with my initial thoughts of easy to assemble in mind.

I wanted to create this surround to be a slide on fit and from then on it could be glued up making the case one complete body.

I sketched from one of the sides of the case and used the slice to see more clearly what I was doing, then projecting the side of the case I could off set and create the shape I wanted for the case, I offset both lines making a 2mm slot and then extruded this the full width of the case and created a new body, I then used this body to cut onto the main case body to sink it into the case so to speak, this would also create the areas where we could glue the surround.

Now to put the idea into practice and 3D Print.

You will see from the attached print preview images on how the prints were laid out to print, initially I printed the 2 sides and the roll top assembly flat to the build plate surface and then printed the surround on it's own vertically printing the knob at the same time.

I set the printer off and waited for the outcome, my initial print was printed in black pla with a white surround.

I was pleasantly surprised with the outcome of the roll top, this was really flexible and from this point on I knew it would work.

With all components printed I could now assemble the case, with this first iteration there was something wrong, I initiall glued the 2 sides together using the base assembly recess and then when I tried to fit the surround I had to force it into the recess, I had glued this before trying it, and was no going back, the roll top worked great by the way, but I needed to make adjustments with the dimension of the side with the extruded base, I did this and printed again in a luminescent green and white surround, this was better but still more adjustment was needed, and finally I printed again in orange pla, this turned out perfect, I trial fitted before gluing together, applied a little vaseline to the runner guides with a toothpick, I used a toothpick to apply glue to the surfaces, I didn't want any over spill which is really hard to remove.

The assembly is easy, fit the roll top assembly into the flat side and then apply a little CA Glue(Don't use Activator) to the edge of the extruded base side or in the recess for the base, align the roll top and sides together and place on a flat surface to dry, then glue the areas on the case where the surround surfaces meet again with a tooth pick and carefully slot the surround into place Activator can be used at this point or just leave to dry, that's it, we have a 3D printed Roll Top Pencil case which works a treat.

This project was a bit hit and miss really, I wasn't sure if it would work right up to the point of 3D printing, but it did work and it worked really well.

I was on a roll at this point and designed a smaller version roll top case purely for Erasers and Pencil sharpeners.

The roll top seems to work whichever orientation is used, smooth side up looks cool, but I opted for the traditional look on the larger case and it worked better smooth side up on the smaller version.

The smaller model is made in 2 sections, glue the knob to the roll top section, fit the roll top into one side glue the edges and pins and align and push the 2 components together, apply a little Vaseline or similar to the roll top guide rails for smooth operation.

STL files for both roll top cases are attached.

Thanks for Looking.