Mini Milling Machine - Exec. Toy

I think that I put more preparation into the construction of the project than any of the previous ones on this Blog. This was the my leaving present to the Head of my DT Department, after 6 years of me asking him annoying questions, using a large chunk of his departmental budget and pleading with him to allow me to stay just another 2 minutes to finish of the last thing. A 2 minutes which almost always turned into another hour as, it was only the last thing if saying it was the last thing would get me to be allowed to stay that little but longer. Keen I know...

So I wanted to give something back and the only way I felt that I could show my appreciation was to put time and effort into making something for him. I decided to build an "executive toy", a table top milling machine, which would not mill but would write onto a piece of acrylic or a postik note, I chose this idea because he was soon to be moving up through the educational ranks and was to become a deputy head. The machine was meant to look a lot like the milling machine that the department had recently bought.

Department Bought MDX40:

My Design:

I set about designing a machine that could be built entirely from 3 and 10 mm acrylic sheets that I would have laser cut. The few other components were a large number of m3 screws, two micro stepper motors that I sourced from a company called nanotech in Germany, a servo motor, an aluminium turned pencil/pen holder, and some buttons and connectors. I also sourced a leadscrew and used some threaded rod for another leadscrew.

Having designed the entire thing on Solidworks I put together some pdf's of the cutting patterns for different sheet thicknesses and colours and took it to another school which had a laser cutter.

Some of the parts such as the acrylic screen did need some bending to be done on the hot wire bender.

They cut them perfectly for me and with the parts all there I began to assemble with the aid of a solvent based fixing agent and some machine screws. It went together pretty quickly and I felt that I should be making a kit version of the project.

Z-Axis assembly:
Inner assembly:

Outer Shell Assembly:

Full acrylic assembly:

The finished project looked great and I was really happy with it. It did need the addition of a driver board but it was primarily intended as a show piece and this was therefore a pointless extra cost.

The gift was complete and a success; it now sits in a display cabinet in the department.

Self contained Wheel/Motor

This was a project I did when I was way back in yr 10, and it too was only for the CAD learning side of things. I still like the idea and I may come back to it, but this is how it stands at the moment. The concept was to have a fixed drive unit that could bolt onto any part of a vehicle. The ring that rotates in the middle was held by 3 other wheels and contains a bunch of other magnets. A coil would sit surrounding the entire ring at the three points where the housing surrounds the ring. This, in theory would propel the ring round. It was originally intended as just a bit of fun and a way of keeping a record of the design idea. If I were to pursue with it now I think the general design would be slightly different.

Key Fob Light

This was a project I did just as a bit of fun, and initially was only intended to be used as a means of getting to know Solidworks cad software a little better. The idea was a single injection moulded key fob light. It would be made of silicon or rubber and it would fit around the end of a door key. Inside it would house a small battery and an ultra bright led, it was dimensioned in such a way that would mean that deformation by squeezing will cause the legs of the led to touch the battery and the light to turn on.

I took the project a little further and decided to design the injection mould as well, this meant that I had to take into account draft angles, split lines and injection points.

I then took it further still by manufacturing a high density foam prototype of the mould and forming a mock-up of it using alginate. I then tried to make a mod-rock cast from the male alginate piece but due to the lack of transfer accuracy and the soft nature of alginate it did not really work. I was good from a learning point of view though and I was happy with the end design even if the model left a little to be desired.

Bridge Valley and Bridge for YR8

This was a job that I had to do when I worked as a technician at my school. Year 8 were looking at structures, specifically bridges, in their DT lessons. The head of KS3, my boss, wanted me to make a river valley for them to test some paper straw bridges over. He also wanted me to make an example paper straw bridge.

I set to work recycling a recycling bin and chopping an irregular shaped v into the longer two sides with a jigsaw. I then drilled a number of holes jest below this new edge. I attached two wooden blocks underneath the handles. I then put chicken wire over the top and using other wire I tied it down using the predrilled holes. Next I used mod-rock to produce a hard surface. Once this was almost dry I used a coarse clay mix and added a more textured earthy looking surface. I attached two more wooden blocks at the top which were to be used as the foundations for the bridges. I then marked a water line in the bottom of the valley, took a photo from the top, pasted the photo into some cad software, scaled it to the correct size, traced the line on the image using the spline tool and then printed the cad design off. I then used this profile to cut out a piece of clear acrylic and place it neatly into the bottom of the valley. I painted the top wooden blocks to look like concrete.

Finally I built a bridge to the correct dimensions out of paper straws and tested its loading capacity using a box of nuts and bolts. This was a quick little construction and took me only about a day and a half.

CTF Siren

This was just a small project that I made for the person who bought my paintball gun turret. He owns a paintball centre and was starting a laser tag game as well. He wanted a slightly more futuristic version of the capture the flag game so asked me to make a police light and siren project.

I used a couple of disco lights and some big red emergency stop buttons. I also took a very, very loud siren sound that was designed to be for a security system, wired them all up with a 12 volt mains transformer which I housed in a plywood constructed wooden box and painted it black. I felt it was quite a neat little contraption and served the function well.

My friend Charlie also decided to demonstrate what a policeman should look like... Oh dear...

RGB Bottle Scanner Recycling Station

This was a project that I did a lot of work on helping a friend out with an a-level project. The basic concept was an automatic glass bottle sorter. The idea was to get more reliable sorting done at the earliest point in the recycling process. It was also intended to be cool to watch and therefore an incentive for people to recycle. The system worked on 2 levels and sorted into 3 colours. It only worked with cylindrical glass bottles as it relied on them rolling down a slope. The system worked using a mixture of mechanical and electronic sorting. The bottle would roll down the first ramp into the reading zone. It would then hit a micro-switch which would activate the RGB colour sensor. This would read the bottle colour and set the pneumatic actuators so that the flap over the correct door would open. The bottle reader would then lift and tip the bottle onto the lower ramp while stopping any previously lined up bottles from pushing past. The bottle would then fall onto the lower ramp and through the appropriate open door into a bin which sat beneath. The reader then returned to its original position this would cause the next bottle would fall into place and the cycle would repeat.

I had to stop helping my friend out with this project when the final deadlines started to approach as I had to continue with my own work and as a result it was never complete this was a shame as the entire mechanism worked beautifully and we got the control circuit working fine on the test boards. There was just not enough time to put it all together.

Automatic Light Switch

This project was a compulsory project that I had to do in my last year at my senior school and therefore it had two whole portfolios to go with it, I will not be putting these online however, I felt I should just give a quick summary of what it did, the idea behind it, and how it worked.
The project I chose to do was a new form of automated light switch that would, using a dual beam system, count the number of people going in and out of a room. It would then turn the lights on or off according to the number of people in the room. The idea was fairly simple and therefore I decided I would expand on it slightly. I decided that as well as this basic operation it should also:

· Fit into a standardised double din wall box housing.
· There should be no visible fixings (so the standard m3 screws would have to fix and then be hidden in some way.
· The housing should use capacitive touch sensitive buttons, which I had not worked with before.
· The switch should also be able to function in an entirely manual mode, with predefined mood lighting levels available as well.
· The switch should be able to output the information about room occupation numbers for security systems, fire evacuation systems, and hotel lobby systems.
· I also wanted to incorporate an LCD screen to display information.

The assembly drawing below shows the exploded cad view of the complete design:

The project used a rapid prototyped clip that acted as the backbone of the project while also clipping into the frame that was screwed into the back-box. This solved the problem of hiding screws. I computationally tested this for injection moulding and stress analysis before manufacture. It was also designed with all the required draft angles taken into account for mould manufacture.

I could not find any capacitive sensing buttons so I designed them and lathed them from steel and aluminium bar, I then tested them on a breadboard. The acrylic separator was clear allowing them to be backlit.

The system was based across two PCB's that sat one on top of the other; the bottom one contained the brains while the top had all of the connections for the LCD display and the buttons. A large heat sink took up much of the space on the bottom PCB for the voltage regulator part of the circuit.

I made a section of wall and doorframe to mount my project in and I recessed the back-box. The light gate was contained inside a single housing and used a reflector to make the beam system work.
The project worked although the clip could have been a little stronger in holding the panel in place. I was happy with the results of this project and got near full marks in it.

The Paintball Gun Turret

This was an idea that was born in the summer after I finished my GCSE's. Originally I wanted to make something, anything, to pass the time. I started work on designing a BB mini gun, but soon realised that the small components would be difficult to manufacture using the equipment that I had available to me in my school workshop.

The need to make was still there however, and being a teenager "guns" featured heavily in what would be cool to make. The next idea was to start building a paintball gun turret. The idea was simple, big, but simple. We would make a seat section with 2 or more paintball guns attached. This would pivot between two uprights and these would sit on a base which would turn left and right. The frame would be welded from tube steel, and the drive would either come from geared dc electric motors or from a pneumatic actuator system. I say we as I am referring to myself and my friend Matt who helped me throughout the project.

We decided that the total cost would come to about £500 and we felt we could get this money together over the time of the build. So we set to work designing, and cutting and welding, visiting scrap yards for vehicle chairs, and purchasing pneumatic cylinders.

The progress was good at first and with the aid of the cad designs that I put togeather the frame came togeather.

It slowed as time went on due to school work and a relatively small amount of commitment at points. We pretty much stopped working on it in the run up to our a-levels and the project was left dormant for a long while. Finally, with interest from the London Paintball Centre, for prospective purchase of the turret we were spurred back into action. The school had offered me a job as a DT technician so I had access to the workshop at almost any hour. There were numerous set backs along the way and many parts had to be remade due to poor design by us and also due to the fact that many things were changed part way through such as the guns, the base support system, the drive system and the electronics setup.

If this project did nothing else, it taught me an awful lot. The project was finally taken of our hands three years after starting and costing just less than 3 times the original budget. This was the first large project that I have done and was what I see now as the practice for the car that I am about to start work (makeitdrive.blogspot.com)