We were given the brief to design and manufacture a cordless drill.
We were provided with CAD files consisting of a Drill Trigger, Motor and Chuck head. These files would help me determine the final drill size and positioning of the main components. I stared the project by researching different types and styles of drills that are available in the market. The findings showed that most drill have a common shape and ergonomic design. However the design of drill do have an environmental impact regarding the material options chosen by industrial designers. The drill body is constructed of a high density plastic which is
Casing & Welding Plastics
Drill case materials are made from a strong engineering polymer PCABS (poly-carbonate acrylonitrile butadiene styrene) with rubber hand grips. To combine two different types of plastics together with the use of an ‘Ultrasonic Welder’ , this is a process where 2 pieces of plastic are placed into a machine where an ultrasonic vibration heats up the two surfaces till they melt and fuse together permanently. This allows complex pieces to be combined and remain tough and strong. Special jigs can be design and manufactured to hold the fixtures in place while the machine fuses the pieces together. However if you want to separate the different plastics for recycling, that can be an issue as two different plastics can not be easily separated and recycled.
Sketches – Ergonomic Grips
The solution to the environmental issues is to design the drills main body t be easily recyclable by the end user when the products reached the end of its life cycle. My design requires that the drills main body to have the rubber sections be easily removable and interchangeable with other materials.
The Replaceable Ergonomic Grips (R.E.G’s) Are grips to which can be easily unbolted from the main body of the drill and can be switched out for different models and materials depending upon what the end user desires
The other environmental solution was to CNC the drills main body out of scrap sheets of different materials. This can have several benefits to the environment and the end-user. The main reason is to reclaim and reuse materials to which would only be put in landfill. This will also reduce the amount of materials being recycled as they are being used for a new purpose and extending their life cycle.
The other feature is that the drill would be a unique colour and be easily identified by the end users as being theirs. Plywood would be a good candid as its readily available and comes in large dimensions of being 8ft x 4ft in length and come in various thicknesses, 3,6,9,12,16,18,24mm, this then allows the to stack the sheet goods and be able to glue them together to create a billet of material to be then machined .The other feature of plywood is its aesthetics. When plywood is carved or machined the different layer show and create a beautiful pattern showing different depths of cuts.
CAD – Fusion360 !
The most difficult part I found on the drill body was the handle. I was not getting the correct shape nor ergonomics with the skill set which I had, as a result I emailed ‘Autodesk’ the software company and exchanged emails with tone of their support teams and was able to determine how I should do the handle efficiently. Throughout the modelling process I was using SOLID MODEL mode to create the drills body. However I was advised to use SCULPT MODE to create an organic hande for the drill. This mode allows me to create dynamic shapes and surfaces, this area within the CAD was new to me and had more tools to which I had to master.
The other issue I had to tackle was combining a SCULPT component to a SOLID MODEL component as they could clash and cause problems wit the final CAD file. After attempting several attempts to combine the sculpt model to the solid model I was able to combine the pieces together
The Final model has to be able to be CNC on our 3rd axis machine with the use of a 3mm endmill. We decided after much discussion it was better to use a 6mm end mill for roughing out the stock material before proceeding onto the 3mm endmill.
Battery & Case
The battery case was designed around the 1865 Lithium Ion batteries to which we are to use for the drill. I started by gathering the batteries dimensions and was able to create them using the CAD system. The brief stated that we had to use 10 batteries for the main drill battery case. I used an existing drill for reference as a means to recreate the locking latch. The best layout for the batteries was to stack them 2×5 formation as this uses the smallest amount of surface area. The battery uses 2 buttons to disengage itself from the main drill body to be able to be recharged and stored away.
After the CAD file for the battery was completed I then proceeded to 3D Print the battery using our Ultimaker2+. I used Polyactic Acid (PLA) as filament for the final prototype.
The charger was an additional part to the drill project. I believed that the drill should have a charging station to demonstrate how the battery would be charged by the end use.
I assigned myself the challenge of creating this charger to be able to hold a battery. However during the process I discovered that I did not consider the tolerance gaps between the charger and battery was to tight and would not fit together. If I were to do this project again I would allow myself a 1mm to 2mm tolerance gap to allow for material thermal expunction and contraction as-well as paint thickness.
The finishing process of this charger took many hours to sand and finish as this charger was 3D Printed in a standard layer count of a 0.1mm per layer.
Unfortunately during the manufacturing of the drill charger there were a few technical issues to which had to be resolved. The first model was created ‘Hollowed’ and the model collapsed on itself and had to be remade from scratch. The second attempt was also a failed print as the bottom of the 3D printer platform was to hot and caused the bottom of the model to warp and deform, at this point I decided to do a third attempt and was successful as it had the correct amount of end fill and the correct platform temperature. The charger looks aesthetically pleasing to the views and was a challenge to achieve.