Overall i feel that i have learnt rather a lot over the course of this module. Initially i wanted to use traditional tools to show my level of skill but in the end it was a bad choice of wood sealer that killed the model off. I have used Solidworks to create the 3D model. This is a piece of software that i had not previously experimented with.
I have become far more confident with spraying items and learnt how to achieve a high quality finish by using fillers.
I am disappointed that the wooden model did not work, with hindsight i would use a different sealer and experiment more with sealers and sprays. I am over the moon with the quality of the finished piece especially as i thought i would not make the hand in date. The Blogs, Prezi presentations and QR codes have highlited the many ways that modern technology can be used. I feel the Blog has given a better incite into my feelings throughout the build than a traditional paper portfolio ever could.
All the photos on this blog and on the images site have been taken on my Mobile phone. The joy of this and the fact that the MATEC has WIFI, has meant that every picture taken has been uploaded to the internet instantly. This has meant all my pics are in one place and not scattered over pen drives, memory cards and folders over several computers.
Honestly i have enjoyed this module although at times i have felt like destroying everything and throwing it in the bin. At the end of the day, most of my problems have been overcome and i am happy with the result
Woodys SDT3101 Blog
Thursday, 15 December 2011
Building the board
So, by this point i had decided on a name. MediSeal and i had already come up with an idea for the display. I wanted to keep the board and display box simple and "clean".
I had thought of using a light box to show off the model but in order to keep the lines of the display clean i wanted to hide any obvious lights.
I decided to create a light box stand with a reverse etched top face. this would allow any writing to show through when lit but not be obvious when not lit.
I chose a font and cut out the design on the laser cutter. Then used a thinner piece of plastic over the top. Initially i intended to light the box with red fairy lights, this proved to be a problem as the lights gave of varying intensities of light depending on how far away they were from the surface of the box. In the end i used some Surface mounted Light emitting diodes (SMLED). These give of a high intensity constant light and can be cut to any length.

Once these had been stuck to a perspex sheet and placed behind the light box the lettering would shine through.
So time to attach my images to the board... also i created a mock up of the device in use. This would show what the model was intended to do without having to write a detailed explanation.
To be honest and without blowing my own trumpet i am quite good with Photoshop. Years of photo-manipulation has stood me in good stead for this task.
I found an image or surgeons on the Net. Took one of my shots of the model. Reduced the size and masked the model image so it looked like one of the surgeons was holding it. Next i created a red gradient over the image and then masked a triangle to look like a beam coming from the device. Et Voila. One finished image of the MediSeal in use.
So i had the images, the display box and the light. all i had to do was put them all together. The finished board looks like this.
I had thought of using a light box to show off the model but in order to keep the lines of the display clean i wanted to hide any obvious lights.
I decided to create a light box stand with a reverse etched top face. this would allow any writing to show through when lit but not be obvious when not lit.
I chose a font and cut out the design on the laser cutter. Then used a thinner piece of plastic over the top. Initially i intended to light the box with red fairy lights, this proved to be a problem as the lights gave of varying intensities of light depending on how far away they were from the surface of the box. In the end i used some Surface mounted Light emitting diodes (SMLED). These give of a high intensity constant light and can be cut to any length.

Once these had been stuck to a perspex sheet and placed behind the light box the lettering would shine through.
So time to attach my images to the board... also i created a mock up of the device in use. This would show what the model was intended to do without having to write a detailed explanation.
To be honest and without blowing my own trumpet i am quite good with Photoshop. Years of photo-manipulation has stood me in good stead for this task.
I found an image or surgeons on the Net. Took one of my shots of the model. Reduced the size and masked the model image so it looked like one of the surgeons was holding it. Next i created a red gradient over the image and then masked a triangle to look like a beam coming from the device. Et Voila. One finished image of the MediSeal in use.
So i had the images, the display box and the light. all i had to do was put them all together. The finished board looks like this.
And that is the end of the modeling task.
Final details and colour
The model was sanded around the join and then sprayed again with high build primer, this gave an even coloured surface to start applying colour. The model was placed in the spray booth and i started to apply a fine coat of my apple jack colour. This was left to dry overnight then lightly sanded to remove any imperfections and get a smooth base coat of colour. These steps were repeated a further three times until the model had a smooth even coat of paint.

Finally the model was finished. Now it was time for the display board

Finally the model was finished. Now it was time for the display board
Comparison of the two
So now i have a nearly finished model made of plastic and a nowhere near finished model made of wood and filler. I wanted to highlight the differences in build quality between the two. and so this is the stage to show that. From the point i was at with the wooden model i would of had to spend literally all my time sanding the filler back down. The problem was that as the filler was sanded down it started to reveal the wooden skeleton of the model. This was the material that i was trying to cover as it was the surface that was reacting with the paint, so more filler had to be applied before it could be shaped and smoothed.
The plastic model also took some hard graft to get to this stage but the joy was i could leave the printer to do its magic and give me a much better starting point than the wood model i already had.
The plastic model also took some hard graft to get to this stage but the joy was i could leave the printer to do its magic and give me a much better starting point than the wood model i already had.
As you can see there is a difference with the shape of the hand grip. this is because i found the curvature of the new model was more comfortable. So... on with the blog and the build
Priming and building
I was now at a stage where i could finally prep the surface of the model for the final coats of colour. Again the pieces were sprayed but this time with a high build car spray. This would fill any of the tiny holes that i had neglected to fill with body filler.


Finally i had a respectable finish on the model. again this was a case of spraying sanding back and re spraying but the 2 days were worth it.
Time to fix the pieces together.
For this i wanted a strong joint that would completely seal the edges. For this I chose Araldite. This is a two part adhesive again consisting of a resin and a hardener. once it is mixed it heats up and starts to "cure" and harden so it has to be worked with quickly. The Araldite was applied to the inside edge of the hole to minimise seepage to the outside of the model. Once applied and the handle inserted it was left for a couple of hours to ensure it was hard. After this the join was covered with body filler and sanded to make the join less obvious
Light at the end of the tunnel
The pieces got a quick sand down to remove any sharp edges. The problem with the 3D printer is that although it reproduces accurately whatever you feed in to it, it does it in steps. That means that every curve is made up of small steps of plastic.

After sanding the pieces were sprayed with a specialised plastic primer. This would start to fill any holes and stop the paint from reacting with the plastic.
After the first coat it was obvious that a lot of work would be needed to achieve a high quality smooth finish. As you can see from the photos this is not the rounded final finish that i wanted. So again more sanding and spraying and sanding and spraying. This was repeated over 3 days leaving the model overnight each time for the paint to dry before sanding again the next day. Slowly the plastic started to resemble the finish i was aiming for.


After sanding the pieces were sprayed with a specialised plastic primer. This would start to fill any holes and stop the paint from reacting with the plastic.
After the first coat it was obvious that a lot of work would be needed to achieve a high quality smooth finish. As you can see from the photos this is not the rounded final finish that i wanted. So again more sanding and spraying and sanding and spraying. This was repeated over 3 days leaving the model overnight each time for the paint to dry before sanding again the next day. Slowly the plastic started to resemble the finish i was aiming for.
But yet again i hit a problem. The plastic handle was starting to peel at the edges. Now it was time for the dreaded body filler. Again this was used to fill any gaps and get a smooth finish. Fill, wait for it to dry, sand and repeat. At the same time there were still some ridges in the upper part of the model so the top was filled at the same time. Yet again over another 3 days the model was filled and sanded

Time for CAD/CAM
During the night i created the model using solidworks. This is a 3D modeling program. Once a model has been built you have the ability to save the model as an .STL file. This can then be transferred to a rapid-prototyping machine or 3D printer. All the measurements of the wooden model were replicated on the 3D modeling software. The only difference was that this time i created a slot in the bottom half of the upper part of the model, This would allow both parts to be prepped separately before being glued together and sprayed.
Now it was time to print the parts. The pieces were fed into the rapid-prototyper and left to build the model. I made sure that both parts of the model were built to be 5mm thick. This would mean that the pieces could be sanded without breaking the model.
The model took 9 hours to print, so the next day i was able to start on the finishing of it.
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