Design Feedback on Power Tool Design
Nicholas_L
| Posted in Power Tools and Machinery on
We are three high schoolers from Sato Academy in Long Beach, California taking a product development capstone class. Our project focuses on building a power sander capable of sanding curved surfaces and we are looking for feedback on some of our brainstormed designs. We would really appreciate it if you could briefly look over our three attached ideas and provide some feedback on the usability or feasibility of the designs.
Thank you very much!
Replies
Not a fan of option 1. It relies on narrow points of contacts. I suspect that small contact patch will wear quickly. Changing paper looks to be time consuming or requires custom supplies
Option 2 and 3 look to be similar and an upgrade to a common tool. I like the idea of an easily adjustable platen in option 2 so as not to require multiple sponge profiles in option 3
I agree
Also if this type of sanding head is simply a hook & loop attachment you could provide molded heads for "standard" profiles in addition to the adjustable radius style.
As for style 1. Rather than a spring loaded approach which has the probability of losing detail as the individual pressure points float up and down. I might take an approach like a contour gauge, where the tool is pressed against a profile to register a negative and then locked in that shape
You also need to consider that you "normally" should sand along the direction of the wood grain. If you sand across the grain you will not get the smooth surface you're after. Concept 1 will be problematic in that regard.
I think you need to draw the radius (3" concave and convex) that you have to accommodate full scale. Those drawings will let you see real quick what you're up against. Conceptual sketches "not to scale" are OK for initial brainstorming but scale drawings are essential.
Good luck!
I don't see where you've considered lateral slippage & 'jumping' when the paper contacts sudden grain changes or knots. Otherwise, a sound start.
Sorry to break your bubble but none of these sanders will work for a lot of reasons. One of them is that to vibrate it cannot be constrained otherwise it will vibrate in your hand but will not transmit vibrations to the wood thus 2 and 3 won’t work.
There is however a tool that exists that would only need a custom attachment and dust collection to perform the task but before I name the tool, I need to know if that would be considered cheating would you use it in your design class.
Thank you for the feedback. For our class, we are allowed to take an existing product and modify it (that is why most of our designs so far are based on palm sanders just with a modified attachment).
There are other sanding tools than palm sanders. Actually I know one that fits the bill right of the shelf.
Option 3 relies on custom abrasive sponge heads, not exactly in the spirit of the design challenge and hard to extract dust through. Option 2 reminds me of the Stanley radius plane. Look it up, Stanley tried various versions of the mechanism and from most accounts it was a bit of a dog.
Option 1 has promise. If you went to a field of pins rather than a series of slats and put small hook/loop flats on them like on the ball-jointed end of a clamp screw you would have a variable surface countour in 3-d. A flexible abrasive like Abranet might work well for it.
Interesting.
I like the effort you have put into this, and it was wise to engage a focus group!
No 1 won't work - the only way to make this effective would be to have the pins stiff and sprung, which precludes the use of store-bought paper. you could use carbide though, which lasts a very long time. Pins would probably jam with dust over not very much time.
No2 would be fine for things like coving and mouldings, but the idea of having to change the shape manually is not pleasant. It would need to be very carefully adjusted in order to match the curve to be sanded exactly, but this has the advantage of not changing that radius.
No3 would be the easiest as it's just a random orbit sander with a pad, but I don't think it meets the brief as pads soft enough to conform significantly will also not transmit the vibration to the paper - the paper will sit still and the foam will vibrate until it tears.
I think that 2 has the best chance of working, and because it can be fixed in position is the most commercially viable - many commercial shops need to sand the same curve often. consider whether you could change the profile using a stepper motor. The way to change the profile is not with a vertical screw, but by forcing the edges of the plate closer together or further apart.
Best of luck - there is probably a good reason why no-one has done this already...
Here are a few tips. Sanding is not meant to shape a part, that is done by machining or carving, sanding will remove tool marks and give an even texture. The problem statement has assumptions that I feel are not true and therefore has oriented your work in the wrong direction.
Problem Statement:
Design and construct an electrically powered sander capable of sanding tight-radius convex
and concave surfaces. There is not an all-in-one, versatile power tool to sand circular surfaces
of various radiuses. Current solutions, such as palm sanders and belt-sanders, are not
equipped to sand tight-radius curves efficiently.
Lastly, a convex surface can be sanded by just about any flat sanding tool, palm sanders, Random orbital, belt sanders and Multi tools such as a Fein. Concave shapes can be accessed by the front roller of a belt sander, a soft pad on a drill such as used in bowl making, a drum mounted in a drill or a special attachment to a multi-tool. Here is some inspiration to your design :
https://www.leevalley.com/en-ca/shop/tools/power-tools/sanders/68298-festool-duplex-ls-130-eq-linear-sander?item=ZT567852&utm_source=free_google_shopping&utm_medium=organic&utm_campaign=shopping_feed&gclid=Cj0KCQjwrJOMBhCZARIsAGEd4VFyP6_qftav5Pz4M3bgqkt_Y7yxf3tbc26tll3TbWOIzx76O4mf6nUaArgKEALw_wcB
https://www.leevalley.com/en-ca/shop/tools/supplies/sanding/discs-and-pads/49254-tim-skilton-premium-sanding-pads?item=68Z2532&utm_source=free_google_shopping&utm_medium=organic&utm_campaign=shopping_feed&gclid=Cj0KCQjwrJOMBhCZARIsAGEd4VHE3B1ssk6aWP78aAB_P_r-XRR911RsF7Ih8dYtWS2E2zX39BmbglwaAq9aEALw_wcB
https://www.homedepot.ca/product/blackdecker-7-amp-3-inch-x-21-inch-dragster-belt-sander/1000162379?eid=PS_GO_140203__ALL_PLA-526641&pid=1000162379
https://www.atlas-machinery.com/makita/dbs180z/
https://www.qualitytoolsonline.ca/products/profile-sanding-set-63810031010?variant=91162509336¤cy=CAD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2020-09-11&utm_source=google&utm_medium=smart_campaign&gclid=Cj0KCQjwrJOMBhCZARIsAGEd4VHq7xqy-R_QkGPfRiz2zTexJeVXkMWJ3JHd9KXw7UN6kuoI-Agg3Z8aAt_mEALw_wcB
I would start by acquiring a multitool. You can go expensive or cheap. I'd go cheap. I don't know the current prices but I purchased a variable speed model for $35 at harbor freight and one day walked in and they had single speed ones on sale for $15 so I bought an arm load. They work OK. I'd either use an offset multitool saw blade, ( the attachments are universal ) or machine something more substantial using a saw blade as a model . I'd design a holder for different profiles that I made out of hard rubber that attaches some way( you work it out) to the attachment you made to the machine. It would be possible to design your rubber profiles so that some small standard size sanding drum ,some would call that a belt, would fit around them. I'd probably use self sticking sand paper or just glue the sand paper to the profiles with contact adhesive. Tools like this do exist though. I once purchased a Porter Cable Profile Sander. I still have it but it isn't very good and I pretty much don't use it. The supplied profiles on the other hand I use often but I use them by hand with adhesive backed sand paper.
If you were to take this to Shark Tank, I think #2 has the best possibility of making it through.
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