Wednesday, 23 March 2011

FMP - Ten (17/03/11 - 23/03/11)

First off, the letters are finished; they had their big night yesterday and I was working right up to the deadline. I had all the letters made by Friday afternoon so the start of this week was focused on finishing them. There was a bit of trouble with the finishing as I was originally going to spray them, but with their large size and there being seven of them I'd have used far too much thinners and paint to justify it when they're going to be drawn over anyway. As a substitute they were just going to be painted with white emulsion, but with time against me I didn't have all of them painted by yesterday afternoon when the workshop closed. So I had to take the letters to the event, on the way picking up some paint as well, and paint them in the back with a few of the organisers as well as several of the charity members. Needless to say they were done on time and put on the tables during the event and within seconds people were drawing all over them. I didn't take any photos last night but I made sure the event photographer (Jade Evans) took some. All I had on my phone was the finished letters un-painted:


With the letters done and just over two weeks remaining I jumped straight back into the carousel. I spent the better part of the day finishing the base off as well as trying out the bearings (which are three part ones). The bearing sits in the middle part, which will be cladded with mirror styrene, on top of the acrylic rod as seen in the photos:


It sits about 2mm above the middle section so the actual rotating parts have nothing to collide with. I was originally going to use felt between the acrylic layers, to lessen friction between them but after taking advice from a fellow course mate I tried out bearings. The bearing now takes all the weight of the rotating parts and is completely out of contact with any static piece. 

Tomorrow I plan on finishing the base, giving it its final coat as well as the front cladding. Along with that getting the rotating pieces fully assembled, so that I can start building the above structure. The biggest task, and no doubt the most important is the sculpting of the characters, with time ticking down I've been thinking about CNC machining them, but with there still being a large queue for it I may just have to stick with my hands.

Wednesday, 16 March 2011

FMP - Nine (16/03/11)

Along with my carousel I'm also building an exhibition model for the 'This is an Adventure' event next Tuesday (22/03/11). For the last event back in February, titled 'Up in the Air', I made a Zeppelin which was hung from the ceiling, with the event title engraved into the bottom side of the cabin. These two projects, which are both live and showcased in a public scenario  make up the other half of my brief, which was originally going to be an architectural model.

Moving onto the model, while it has nothing to do with the event itself, a local charity against human trafficking approached the organisers at the last event and asked if they could have something to show this time round. They wanted the word "FREEDOM" in large letters, with each letter being individual mobile so that they can be placed on different tables and wrote on by the public

The font is Nevis and was chosen by the organisers of the event who also came to the agreement of each letter being 450mm high with a depth of 250mm. Once I had the font, I just scaled it up in Rhino and exported it so that it could be lasered.

I managed to get three letters done today, F, one E and M. Each started off with the front and back panels threaded with dowel cut to 250mm:


They were originally going to be cladded with styrene but that would use up a lot, so I opted for 3mm MDF and 1.5mm plywood for curves. This of course boosted the overall height to 456mm, but that isn't a problem, considering the wooden cladding makes it overall stronger than styrene would have:


For letters, such as the F, which are either top heavy or will have a problem standing up, weighted metal rod was threaded parallel with the dowel:


Here's what they look like so far, of course they still need sanding, filling and spraying:


Here's a link to the Thisis site where more information is available about the event:

Tuesday, 15 March 2011

FMP - Eight (10/03/11 - 15/03/11)

To be honest, progress has slowed down a bit over the past 2 weeks in getting the base finished, but at least I can proudly say that all the work and time has paid off, as the CAM works! It's been sanded down to create a smooth track, so of course I assembled the bits I have to give it a test run. I didn't attach the motor, so it was rotated by hand, but nonetheless it worked. The masking tape represents the different height changes as it's rotated:



As you can probably tell, the rod going round isn't one of the ones I've made. I tried the ones I made on it last week (before the CAM was probably sanded down) and it snapped the ends off, probably due to catching on some protruding filler:

As I mentioned this was last weeks attempt, since having sanded down the CAM, the ones that still have the ends work fine. But this problem has highlighted the issue for me, so even if I stick with the tyre idea there's a good chance of them snapping and there's nothing I can do to fix it. So to prevent this I'm going to sand the ends down into half a sphere, just like on my prototyping. This instantly strengthens the end tenfold, and is a lot less fiddly than the tyres. It's worth noting as well that I was only using the tyres when the CAM was only 5mm thick with guides either side so that it couldn't rotate, but now it's almost tripled in width and there are no more guides this idea wont work.

The new design to prevent them from rotating is to simply thread a bar through the poles and have two pieces attached to the base, so that they prevent the pole from rotating, this picture should clear that up a bit:



To end on a good note, here's a video of it working (keep your eye on the masking tape):

video

Wednesday, 9 March 2011

FMP - Seven (9/03/11)

As promised here are the photos from what I mentioned in yesterdays update. To create a fillet with lasercut sandwiched pieces, the top and bottom layers have to be slightly offset inwards from the outer edge. This is what they start as, with the two thinner pieces sandwiching the larger piece:


Once lasercut and attached to each other, they are covered in filler:


And then finally sanded back to create the fillet and give them an overall more circular appearance:


The larger piece is what attaches the lower moving base to the top, they slot into each part:


Moving onto the new CAM, here it is:



As you can see it still needs to be sanded down and filled, but it has fixed the alignment problem thankfully.

Tuesday, 8 March 2011

FMP - Six (4/03/11 - 8/03/11)

A lot has happened since the last update, on the one hand I got the carousel working at the end of last week, but then on the other there's been a serious alignment problem.

To get the bad news out of the way, somehow, even though I used templates straight from my digital model, the centre MDF piece is lopsided, and as a result this has had a knock on effect of everything which surrounds it, most importantly the CAM. The now realised off centre CAMs and MDF piece:



As it is lopsided, the above slot for the vertical poles to slide down doesn't accurately follow the CAM, and in other places falls off it. Being only 6mm wide, there isn't enough room for this leeway, so I've had to extend it's width by sandwiching the original CAM with two 5mm lasercut and then heatbent acrylic pieces, I've yet to get a photo of this, but I will for the next update. 

The problem doesn't end there, as the original CAM was only 6mm wide and sandwiched between two higher matching styrene profiles, to create a trench, I could use circular vertical poles, as the wheel they'd be attached to would prevent it from going on its side (a massive problem with my mock up). But now the width has been extended to 16mm, this prevention is useless, so I've had to redesign them so that they are now more square thus unable to rotate. This does have its upsides though as due to the cartoonish nature of the carousel, these poles were going to be heat bent, and for the wheels to be attached they'd have to be milled at one edge. But now these poles are made up of a 3mm profile sandwiched between 1mm thinner profiles, which will be filled so that it has somewhat rounded corners. Its cutout in the base is slightly larger than this, but due to the square sides and edges it prevents it from rotating. Photos to better describe this fix will be uploaded tomorrow.

Moving onto the good news, getting it to work. This started with lathing the aluminium bar to create a hole in one edge for the rod from the motor to slide up to. A perpendicular hole was then drilled to penetrate this hole, and this hole was threaded in turn so that a screw could be fitted. The rod from the motor has one flat side (which doesn't show up too well in the photos) which is meant for an external screw to go up against. All in all this prevents the bar from freely rotating while attached.

The bar attached to the motor:


The hole in the edge where the rod slots up:



The blurry flat edge of this rod:



In celebration of it working, and the top piece successfully rotating the bottom one I recorded a short video. Even though this was the moment that highlighted the alignment issue, it is still worth noting.

video

Thursday, 3 March 2011

FMP - Five (3/03/11)

Progress is moving quickly with the baseboard. Today marked the most important part of my model, the CAM, in that getting it into shape and attaching it to the base. After having figured out the circumference issue to get it perfectly wrapped round, I lasercut the hilly design in 6mm acrylic:


To transform it into a circle I needed to heatbent it, having learned the hard lessons of heatbending from the previous project, I made a negative and positive form for the job. Once the acrylic was flexible enough it was pushed into the negative former:


In order for it not to warp and cool back on itself the positive former was then pushed in:


I needed two formers due to the different diameters of the two CAMs. They were made in the same way as my base ring, that is using a router. Even though I had the correct length for these heatbent pieces, there is a gap where they meet due to the rounding down of circumference values when halving it; I tried filling it using the formers but it didn't work as well as I hoped, so I plan on doing this when they are attached in place.

I also made the supporting MDF cylinder for the mirrored part (as shown in the last update), which had to be at a set height so as not to be visible. The 25mm acrylic tubing sits on top of this block and then runs up inside of the mirrored part. 

It's important that the CAMs are in the correct position, or else everything above it goes to waste. To do this I lasercut styrene doughnuts as seen in the two below photos:


The outer/larger CAM is not yet attached due to a lack of styrene doughnut but this will be fixed in place tomorrow, and then both can be filled and sanded. Along with that I've also got to cut out the 0.5mm styrene runners which sit either side of both CAMs to prevent the wheels going off.

To end on a bad note I realised tonight, when assembling it that my lasercut pieces (the actual parts which rotate) were taken from an old model and as a result the holes cut out for the actual vertical poles which run over the CAM were out of place.

Wednesday, 2 March 2011

FMP - Four (21/02/11 - 2/03/11)

First things first, I've started on the final model, working from the base up. This means the baseboard of course came first, followed by the base structure. Last week was also spent waiting for things to arrive, such as my new springs, wheels and most importantly my aluminium square bar (which everything rotates off).

To have something to build from I needed a digital model so I begun working on that, using all the information I gathered from my mock up models, such as gaps to avoid collision and the below CAM. The baseboard is also more complex than a usual one, considering I needed to fit the motor, switch and battery pack into it. The switch (like most off the shelf ones) has an inbuilt tension/locking device which allows it to be slotted into a hole that matches its size and the device then holds it in from the back. The MDF I used for the baseboard was far too thick for the device, so I milled out a slot in one side and place two lasercut acrylic layers for it to sit into:


The most important part of the baseboard is the location of the gearbox motor, in that it has to be perfectly in the centre or else everything will be off. To achieve this I used two runner MDF pieces (the double thick MDF edges on the right and left of the below photo) and a printout to make sure it was located correctly:


Going from my initial designs I also digitalised the centre part of the carousel, which is fixed to the base. In order to make it more carousel like (I originally was going to have Dr Seuss photos in the frames) I opted for mirrors, the mirrors used are 2mm mirrored styrene with 1mm styrene cladding in irregular shapes to give that 'cartoony' look:


To hide the CAM and to allow the carousel something to slide over an outer base ring was made from two MDF pieces done via a router, with 2x4 (all cut to the same height) sandwiched between to achieve the overall height of 50mm. An acrylic top sits on this base with holes cut out for acrylic rod which goes on to support the above stationary structure. To hide the exposed sides, it will be cladded:



After spending a week waiting for my sqaure bar to arrive I decided to make me own, sadly that evening upon returning home I found it waiting for me, after being delivered during the day. Needless to say I was happy to see it arrive, but I wasted an afternoon on taking down a larger bar:


In more recent news I'm looking into possible colours to match the Dr Seuss theme:

The solid colours for the base don't work, so I'll probably add a streak design into it, something to break up the colours, such as this (which is from the Dr Seuss island at IOA):