‘Susegad’ comes from the Portuguese word ‘sossegado‘ for quiet is a term used in Goa. The people of Goa, also referred to as Goan consider susegad to be a part of their personality. The word susegad refers to the laidback attitude of the Goans, who seem to live in a state of contentment and relaxation throughout the year. As part of the final project for ME318, I decided to capture this attitude of Goans in a product. Susegad is a holder for miniature alcohol bottles and shot glasses.
“To escape and sit quietly on the beach – that’s my idea of paradise.” – Emilia Wickstead
When the class had to begin thinking about the different ideas for the final project, I had decided to dedicate this project to my mom and dad. I wanted to make a project as a token of gratitude for all they have done for me. After going through different product ideas, (none of which seemed interesting enough to pursue) I decided to get down to the basics and think about the core reason behind this project. My mom and dad did everything they could to give me the best in life. Now that it is time for me to begin my career, I wanted to let my parents know that they can sit back and relax and live the rest of their lives in contentment, much like the Goans do. So I decided to follow the theme and turn the project into a Goa theme project. Goa is known for its beautiful beaches, nightlife, alcohol and its hospitality. Following the beaches and alcohol part, I decided to make a holder for an alcohol bottle. My mom loves to collect different mini alcohol bottles and shot glasses. This product would be the perfect addition to her collection.
DESIGN PROCESS & PLAN OF ACTION
Keeping in mind the beach theme, I decided to look at the different aspects of the beach that I wanted to capture in my project. Coconut trees and a hammock seemed like the perfect beach theme objects to go ahead with. The product would be two coconut trees between which a hammock made out of wire and wire cloth would hang. This set up would sit on a box with a drawer. In the drawer shot glasses would sit with the help of a wooden plank with slots made in it. The beach effect would be replicated by the use of epoxy resin, different resin inks, and sand. The initial sketch is shown below
After making the initial design sketch as shown below, I noticed that I had a lot of different components that need to be made individually and on different machines with different materials. I wanted to make most of these components on the CNC. It seemed like a lot of machining to do and involved a lot of part flips. So I further broke the tree and the hammock into components. Using some lateral thinking while designing these parts for manufacturing, I found other easier manufacturing methods for the hammock and the leaves of the trees. The breakdown of the individual components is shown.
I knew I had taken up a lot and decided to start working on the different components ASAP. The Gantt chart helped me follow my plan which helped me complete my project in the end.
The Gantt Chart helped me in planning out and keeping sufficient time for manufacturing of the different components. After quickly generating the files for the Laser Cutter and the Water Jet cutter, I decided to move on to the essential part of this project, the CAD and CAM and eventual manufacturing on the HAAS Vf2 3-axis milling machines.
DESIGN & CAD
The initial plan of the CAD was to work with surface modeling for the tree trunk. The surface modeling would help with adding a natural look to the tree trunks. However, after looking at different images of the trunk as well as some CAD ideas online, A simple loft with a guide curve worked perfectly for me. Since the overall piece was very long, I decided to make both trunks with one stock piece. The orientation of the job was important as well. I wanted to avoid multiple part flips and decided to orient the trunks in the horizontal orientation. I decided to model the thin web and the workpiece as well so that it becomes easier to use HSM works and make and easier CAM with lower machining times.
The design for the leaves and the slots for the shot glasses were made easily on Adobe Illustrator and then manufactured on the waterjet cutter and the laser cutter respectively. The size of the box and the drawer was done by performing some manual calculations. Since the final layout of the trees depending on the sand and the flow of epoxy, making the CAD of the final assembly seemed futile.
Once the CAD file was done, it was relatively easy to create the CAM program required by HAAS Vf2 3 axis Milling Machine. I had to divide the machining into two separate jobs. The two jobs involved a part flip and I decided to use the help of wax to support the stock while I machined the other side. Both sides had a similar profile and had a very similar job process. The overall stock simulation showed that it would take approximately 2 hours for rough cutting each job. I decided to use only tools of small diameters since I had small curves and notches that were required to be machined with great detail. This is one of the reasons why the program had a large machining time even though it did not involve a lot of machining. To reduce the amount of rough cutting time, I added an extruded ellipse in between the two tree trunks and this drastically reduced my cutting time to approximately 1.5 hours. Further, I moved to a Carbide tool and could increase the SFM from 300 to 400 and dropped the final rough-cutting time for each job to approximately 55 minutes.
The basic pocket clearance removed a big chunk of the material and a further adaptive clearance ensured the correct curves for the tree shape. To ensure a good finish, I initially did a contour finish for the steep areas with a very small step over and then a parallel finish over the contour for the more shallow finishes. The stepover/ step down for both finishing processes was 0.005 inches. However, I had a long overall machining time of approximately 4 hours. I then decided to change the stepdown for the parallel finishing operation since it was a second finishing operation. This reduced my final machining time for each job to approximately 3 hours.
The actual machining took lesser time than the time I had allotted for it on my Gantt chart which was a blessing. However, the entire process was nerve-racking. One reason why I finished machining this quickly was due to the fact that I did not square my stock before I started machining. Due to the limited availability of manual milling machines, I could only face two sides to be perfectly parallel which were the faces used to probe the X-axis. The remaining faces of the stock were the extruded surfaces of the bar I had purchased as stock. To ensure proper alignment, I decided to select the correct Work Coordinate System for Job 2. I ensured that the WCS in the program would use the same corner for X-axis and Y-axis as in Job 1 While probing the piece, I ensured that I probed from approximately the same point. I was not too concerned about the z-axis as that would just change the thickness of my final product.
The alignment of Job 1 and Job 2 was perfect. The only difference was in the Z-axis where one side was slightly thicker by approximately 0.007 inches. The reason I found this was due to the incomplete machining of the thin web in Job 2. This did leave a thin sheet of metal which was easy to remove with a deburring tool. The finishing operations did not leave any machining marks except for some tiny grooves from the parallel. This left a very natural finish on the tree trunks and did not require any further sanding or finishing.
- Aluminum 6061 block: 7″ x 4″ x 1.25″
- 2″ Shell Mill ( Manual Mill)
- 1/4″ Carbide Flat End Mill
- 1/8″ HSS Ball End Mill
The box was machined using the table saw to create miter joints so that wood seemed seamless. The box was immediately stuck together in the PRL since the further processes depended on the box. The slots were machined on the Laser Cutter and the leaves were machined on the water jet cutter. The leaves were machined out of 0.032″ thick Aluminum sheet. This made it easy to bend the leaves into a natural shape by hand and did not require the use of any PRL equipment. This came handy as I could do most of the assembly at home and did not face any difficulty due to the sudden closure of the PRL. The hammock was made by twisting wire into a skeleton for the hammock and then wrapping wire cloth around the skeleton. A simple pair of pliers was more than enough. The final Epoxy Resin was then poured at home and the box was sanded down and then stained with a Walnut wood stain.
TAKEAWAYS AND LESSONS LEARNED
- “Hope for the best and prepare for the worst”. While making my Gantt chart, I left enough time for machining and overall manufacturing of the product. I followed the Gantt chart as much as I could and this proved quite beneficial for me as I could finish the major machining before the sudden closure of the PRL. Ensuring that I had enough time plus extra buffer time was really helpful and should honestly be done in order to have a stress- free designing and manufacturing of the final project. TL;DR, Start Early!
- “Trust Stock-Simulation on HSMWorks”. While creating the CAM program I did see some weird issues in the Stock simulation. Even though I had put in the correct machining heights in the height tab, some part of the web was never machined off. I trusted the program even though Stock Simulation did not show it. This resulted in an incomplete thin web ( and unnecessary work in the end)
- “Do not be scared of the giant monsters called HAAS CNC machines”. While they seem intimidating, the CNC machines are your friend and will do whatever you tell them to do. Trust your CAM program and the machine will work perfectly. The anxiety does not help you during the machining time. A stress- free design and manufacturing process results in a wonderful product in the end.
- “Always Square your stock”. It will help in the long run especially if you have multiple faces. If you do not plan to, be very careful while selecting your WCS on HSMWorks and probing the stock piece in the CNC (even after that it is a risk some may choose not to take).
- Think Laterally!” Honestly the most helpful of them all. I would have ended up with a weird NY Yankees Lamp had I stuck with my original idea at the start of the quarter. Trust in Craig and do not take it lightly when he forces you to think laterally. Broaden your minds and let the flow change your design ideas.