3D Printed Multi-tool for People with Limited Dexterity
Our project is to create a multi-tool with a variety of functions. Since each individual tool can have a variety of sizes and designs, each member of our group designed their own tool. We compared each tool based on print quality, aesthetics, strength, and functionality. Parts A, B, and C can be seen below, each with their own advantages and disadvantages. We plan to take the best aspects of each design to create our final part.
Part Descriptions
Figure 1: Part A
Part A was printed using an FFF printer with PLA as its material. It was printed face, up as shown in the picture, to require almost no support structure. Additionally, the layer height was increased to make the print faster since fine detail was not required. The part is about 4.5 inches long and fits well in a hand. On the left is a plastic bottle opener with small fins to engage with the ridges on a bottle cap. In the middle of the part is a opening which a Razer blade can be glued in place. The slot along the bottom edge lets the Razer be used to cut a bag while protecting the user from accidental cuts. On the right side the part tapers down to make a small slot for pop tabs. This will need to be refined in future designs because the angle required to open a can was quite difficult use.
Figure 2: Part B
Part B was also printed using an FFF printer with PLA plastic. The infill was turned down to 20% to get it under 8 hours of print time. This part was built around an already existing glass bottle opener design that had good reviews. On the corner is a soda can tab opener that works very well. In the middle is a plastic bottle opener. This part doesn’t have a very clean fit in the hand because it is somewhat bulky. The part is somewhat sturdy and needed little to no support structure, but the corners are sharp and not very comfortable to hold.
Figure 3 : Part C
Part C was printed using an SLA printer with a durable plastic material. Since the part was SLA printed, there is full infill as the part is solid. This part includes a bottle opening feature, a soda tab feature, a twist-off cap feature, and a letter opener feature. There is also a hollow slot within the part that would allow for the installation of a small magnet. This part has rounded edges, and tends to fit well in the hand. Some of the problems with printing this part was the large amount of support structure needed. The surface is rough at points where support structure is removed, and would likely need more post-processing to improve the surface finish. The large amount of complexity seen in the twist-off bottle opener requires a large amount of support structure and post-processing to keep each flange clean. The long slot opening is slightly flexible, which would allow for a small blade to be pressed into the space.
Functionality Tests
Each part has multiple tools attached to it, and these tools were tested on each part by opening twist off caps, bottle caps, and can tabs. The chip bag openers and magnet spots were not tested, though the designs are still compared during these tests. The comfort and ease of using each part was also compared.
Part A consists of a soda tab opener, a twist off cap opener, and a chip bag opener. During testing, the twist off cap opener worked well. It easily gripped the cap, and the length of the part allowed for a considerable amount of leverage on the cap. However, the cap tended to become stuck in the opener, rather than sliding off when the part was removed. The soda tab opener contains a tapered angle to allow for easy tab access, however, the slot designed for the can tab to be inserted into was too small, and it was therefore ineffective at opening cans. The chip bag opener angle was good, however, it is likely too wide to create an effective bag opener. The removable slot allowed for plenty of room to fit a standard razor blade, and the tolerances were well calculated to provide a sliding fit. Lastly, the part is smooth and fits well in the hand, and is quite easy to use.
Part B consists of a soda can opener (which may double as a chip bag opener in the future), a twist off cap opener, and a bottle opener. The twist off cap opener was too small to fit a cap, so this part of the design was not tested. The can tab opener worked very well, and allowed for easy fit under the tab and good leverage as well. After multiple uses of this tool, there was no sign of wear on the can tab opener. However, the highlight of this part was the bottle opener. Even with a small lip supporting the gripping edge of the bottle cap, this part held up under multiple uses with little to no wear. One disadvantage to this part was that it is quite uncomfortable to use and hold. While one could open bottle caps effectively, the large width and sharp corners made it painful to do so.
Part C contains a soda can opener, a chip bag opener, a twist off cap opener, and a bottle opener. The twist off cap opener, while still containing some leftover support structure, was extremely effective and easy to use. The length of the part allowed for a fair amount of leverage and unlike Part A, the caps did not tend to stick to the part. The chip bag opener was thin and tapered, and while a blade was not installed, one would likely be able to open up the slot enough to fit in a small blade. The bottle opener on this part, while more comfortable to use than part B, was not at all successful. After the first attempt at opening a bottle, the material was sheared off and the bottle cap remained shut. Further attempts to open the bottle only marred the opener more, until it was completely unusable. The soda can opener was also quite ineffective, as the design did not have a tapered end. The edges of the soda can prevented the part from reaching underneath the can tab, rendering that tool nearly useless. The SLA printed part had a nice surface finish (where there weren’t remains from support structure) and the edges were smooth, making this a very comfortable tool to use.
Figure 4: Failed soda tab opener on part C
Final Summary Notes
By creating three separate designs, we were able to explore a variety of options which we may use in our final part. We know which options work well, and which we should avoid. From part A, we will likely utilize the large opening and removable slot, which will allow for easy installation of a chip bag blade as well as a magnet for mounting the part.The can opening design will require further testing before it is used in our final design, and the chip bag opener will need to be much thinner for it to be effective. From part B, we will definitely be using the bottle opener, as it has surpassed expectations. The soda tab opener design worked very well, and with a few changes, will likely be used in our final part. However, we also learned from part B the importance of the form of the part. We will avoid sharp corners and square shapes, as they provide very little leverage and can be quite uncomfortable. With part C, while the bag opener was well tapered, we won’t need the part to be very flexible if we can insert the blade from a larger opening elsewhere on the part. We will not be using either the bottle opener design or the soda tab openers, regardless of the material. Although the two twist off cap openers tested worked very similarly, the part C opener was slightly better than part A, therefore we will be using the opener from part C in our final design.
By combining and improving upon these parts, we plan to iterate upon new designs to create an effective 3D printed multi-tool.