Magnetic box - parametric model

#1

I thought I would share a part I made this weekend on the Nomad.

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I got inspired by Winstons video on a wooden jewelry box with magnets (https://www.youtube.com/watch?v=2c6T3NjG20M&t=345s). I noticed quite a few users have made similar boxes but thought I would share mine anyway. I made a parametric box design in Fusion 360 inspired by Winstons design and machined a small tree of life in brass and glued it into the top of the part. As I wanted to chamfer the bottom and top edges of the lid and also machine a pocket for the brass part it turned into a 2 sided machining project. I flipped the stock and relocated it using 4 mm dowel pins by first machining 4.05 holes into the stock and then machining 4.05 mm holes 4 mm into the table after removing the stock to be able to relocate the part using the dowel pins. But if someone does not want to do that it is readily machined in one setup.

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I inserted 5 mm magnets into the part, mindful to orient the magnets in the right direction as a previous box turned into a box impossible to close as the magnets would push the lid off haha…
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I machined the tree of life design from 3 mm brass stock using a 2 mm flat end mill and then a 2.5 mm ball end mill followed by finishing with a 1 mm ball end mill. (I tried getting even more detail with a 0.4 mm ball end mill that broke halfway through finishing).
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As one cannot add depth of cut with parallel toolpath in fusion I used stock to leave to make sure I did not brake the 1 mm end mill and closed in on the nominal dimensions fairly slowly with successive toolpaths with less stock to leave. This is a bit time consuming, is there a better way to do this?

I bought the tree of life design online and can therefore unfortunately not share it. But if someone wants to purchase it, this is where I got it: https://www.cgtrader.com/3d-print-models/art/sculptures/tree-of-life-printable

I polished the brass part with a dremmel tool before gluing it into the lid.

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Here is a link if anyone want to download the fusion 360 file for the box https://a360.co/31dXhsv. The design can be changed by parameters which can be found under the modify tab -> change parameters.
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By changing BoxWidth, BoxLength, BottomPartHeight, TopPartHeight you can change the box dimensions and the design will update by itself. If anyone is interested in using the model feel free to use it for any purpose! Also, the MagnetHole and MagnetHeight parameters govern the holes for the magnets and can be changed to accomodate other magnets but I would not put much larger magnets into the part as it would probably be difficult to open.

13 Likes
#2

Solving this problem for me was to mark my magnets as they come in and while they are stacked. I have a fixture with a “standard” magnet built in so I can mark all of my magnets the same way. I don’t care whether they are “N” or “S”; just the same all the time.

I mark them with a “+” via permanent marker which can be easily wiped off with a bit of solvent on a rag.

This is a good job for my grandson.

5 Likes
#3

Thanks for the advice, that is a better way of doing it and making sure that parts between projects are compatible! I had them all in a stack and removed one after the other and glued them in but that leaves some room for mistakes. Also a nice way to involve your family :slight_smile:

#4

Beautifully executed, what was the total run time in brass?

#5

Thanks @Sherpa! It took quite a bit of time, about 4 hours. The roughing with the 2 mm flat end mill took 10 minutes. I did two parallel toolpaths with the 2.5 mm ball end mill (0,2 mm stepover), one with 0,25 mm stock to leave and one with none, they took 20 minutes each. I did the same with the 1 mm ball end mill but the last finishing toolpath with added perpendicular passes with a stepover of 0.05mm that took 2.5 hours. So in total about 4 hours. It was my first time machining brass so I would definitely speed it up if I make another.

My first thought was that I would try and cast the tree in pewter. I 3D-printed the part and casted high temperature silicone molds that I then casted pewter into but I was not happy with the results (probably due to my none existing casting skills haha…) so ended up machining it instead.

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4 Likes
#6

Thanks @Olle just a follow up, so your material stock was 3mm, what was you depth of cut, final stock base depth, as in the space either side of the stock. I am working on a production project and after seeing this might change design :grin::grin:

Thanks for taking the time to reply, again this is the look I am after so very well done indeed

2 Likes
#7

No problem, happy if it can help! I will check when I get home from work. I could apply the same tool paths to a different part so I can share a fusion file also.

1 Like
#8

no need for fusion file, the final base thickness will be epic- again thanks for helping

#9

The depth of cut for the 3D adaptive with the 2 mm flat end mill was 0.3 mm for roughing stepdown and 0.1 mm for finishing stepdown. I defined the top stock offset in fusion to 0.2 mm so the thickness of the part should have been close to 2.8 mm.