In this assignment we have to make something big with digital fabrication. Assignment include with 2D design, 3D modelling tools. I am going to use Autodesk software for design things and I am going to try part works for fabricating my design on shopbot machine.
Before making design I have few ideas in my mind for fabrication like stool, table, kitchen accessories etc. but I don’t want to go with routine furniture item, I wish to make something which will help for community, so after some research I have selected for Heat Retention Box.

Heat Retention Box

The reason behind selection of Heat retention box was school students, Here in India especially in Maharashtra, government provide mid-day meal to school students,
to cook food for all students is big task for school authority many times teacher’s or outside person involved in such activity, so many time that food was not well cooked and hygienic sometimes
So after searching and surveying I come to know about that Heat retention cooking will addressed all answer regarding such things, which will ultimately solve issue of cooking fuel and students will learn about solar cooking, understand heat retention concept.

Box is placed into an insulated box where it will continue to cook until it is done. Retained-heat cooking is often introduced along with solar cooking since it further reduces the use of traditional fuels such as firewood, and the use of this method allows much more food to be cooked each day in a solar cooker. This method of cooking is also known as retained-heat cooking, fireless cooking, haybox cooking, or wonder box cooking.
Even it stay hot for hours, heat retention box have been made using hay, straw, wool, feathers, cotton, rice hulls, cardboard, aluminum foil, newspaper, fiberglass, fur, rigid foam, and/or other suitable materials as insulation. The insulation is placed between the rigid walls of a box, within a double bag of material, or lining a hole in the ground.Instant haybox have been created by wrapping a sleeping bag, blankets, and/or pillows around a pot. The most effective insulating materials create many separate pockets of air, which slow down the movement of heat. 2 to 4 inches of thickness (depending on the material) are necessary for good insulation.

As per this I am going to make this heat retention box as 'lunch box' to students for mid day meal which will be hygenic and safe for students also it will give cooking experience to students on solar energy. Actualy in India we have mid day meal concept in every goverment school but after many servey it has proved that, the food made school were very unhygenic and not cooked properly. So I did following design for heat retention (lunch) box. Inside box can be placed easily. Its somehow like our regular lunchbox. I am going to made this on Shopbot machine.

I did my press fit design for shopboot machine in Inkscape software. The dimensions of the heat box are 28x28x18 cm with a top hole of 15 cm diameter. Download design file at the bottom.

I exported 2D design in Autocad DXF and check design with 3D modeling too. Then import design in partwork, a software to create toolpaths.

Create tool path in part works. There are only cutout toolpaths in this design. Basic settings below (see image for further settings):
Spindle speed: 12000rpm
Feed rate: 1 inch/sec
Material thickness: 8mm

I created only one toolpath but it is better always create inner path like inside cut for tool path. Then toolpath for out side. Then job will cut perfectly. Also created some tabs using part works for holding material in place after cut.

I used this Shopbot machine located in IAAC Fab Lab Barcelona because I completed this assignment in Fab10. With dimension as per bed size 8*4 foot bed size machine. Bit size used was 6 mm (0.25inch) in diameter with ball nose.

After that partworks exports toolpath to shopbot machine Pradnya.sbp file and ypou open this file in shopbot machine. Material used for making heat box retention was 8mm plywood.

Shopbot machine makes lot of noise while cutting. But after machining process Heat Renton box look like below. Shown here first try because I forgot to click the circle while creating toolpath hence hole did not cut. So I had to repeat.

After cutting second try and assembling my box will look like as per below. Now just fill with insulate material and tinfoil.

Hey one thing I would like to share i.e at Barcelona I meet with Ms.Salley (Shopbot salley), lovely lady who was first introduce me shopbot handybot machine while FAB10 Conference, Barcelona. It was nice learning experience.