Brady Watson
06-05-2015, 08:27 AM
I know a lot of you wanted to attend McGrew's Camp last month, but were unable to. I thought I would post a little project I showed during my presentation. I've been getting a lot of requests for 3D printing applications, which has much higher requirements for clean/closed/water-tight data. In this example I will show how the data can be used for both 3D CNC routing applications as well as 3D printing, although I must admit my 3D printer is just a 'cheapie' so the actual data is better than the print shows.
I thought I would pick something that most of us use on a daily basis - In this case, a 12' tape measure. The original had quite a bit of black rubber (which is very diffuse - it absorbs the light) in addition to some dayglow coloring, which in contrast to the black would scatter a lot of light while scanning. I elected to paint each half to make sure I got good data. This is sometimes a necessary evil with scanning - and in most cases it is OK since we will be able to make duplicates once we have the data anyway.
I started by disassembling the tape and putting the components aside. Each half was scanned on all sides. Some models have deep cavernous features that don't have a clear line of sight, making 100% coverage of the scan tough or impossible. This is where software comes into the picture to enable hole filling etc. I filled in some areas in Aspire that were part of the injection molding process and not necessary for the wood variant. Some of the features on this part were very tiny, such as the little alignment bars at only 0.018" thick, which luckily didn't snap off while machining!
Once the data was ready for digital fabrication, each half was brought into Aspire. Rather than use the data as-is, I elected to add a little flair to one of the case halves using the 3D tools in Aspire. A few lines and a cross-section and a lovely little weave was added for no additional machining cost. Each half was toolpathed and setup to run on the ShopBot. Each half was machined on 2 sides in maple (color doesn't match on them...I just used scrap I had laying around in the shop). I roughed out with an 1/8" and finished with a 1/16" ball. I drilled the screw holes by hand because I wanted to test fit them - but could have done this on the Bot as well.
When machining was complete, I test fit the ones off the machine with the corresponding plastic original. It was a *perfect* fit!!! No file or Dremel work! Now I don't care if any of you are not impressed by this, but I sure am!!! I wanted to seal the halves before moisture warped them, so I put some Watco oil on each half to seal it. Now, there is a reason they don't make tape measures 100% out of wood. If you look at one of the pics, you'll see that the forked mandrel that holds the spring for the tape retraction is glued...I tried to keep it from twisting and snapping, but it just couldn't handle the stress/twisting. I had to glue it. While gluing it (Q-Bond) a little dripped on the tape roll and locked it in place - so the tape won't go in & out now - but that's OK. ALL of the original hardware fit right onto the wood one perfectly. The little detent switch that locks the tape glides effortlessly.
Using the same data, I filled in all of the holes and 3D printed it in plastic. Due to time constraints I just printed the whole thing out solid (20% in-fill) to show how the same data can be used in other ways...So once you invest in 3D data, it's the gift that keeps on giving. You can use the original to make duplicates, or add a little flair to the project. It is also possible to use the data for 3D visualization or to make derivative works to stretch the product line with a similar motif etc.
-B
I thought I would pick something that most of us use on a daily basis - In this case, a 12' tape measure. The original had quite a bit of black rubber (which is very diffuse - it absorbs the light) in addition to some dayglow coloring, which in contrast to the black would scatter a lot of light while scanning. I elected to paint each half to make sure I got good data. This is sometimes a necessary evil with scanning - and in most cases it is OK since we will be able to make duplicates once we have the data anyway.
I started by disassembling the tape and putting the components aside. Each half was scanned on all sides. Some models have deep cavernous features that don't have a clear line of sight, making 100% coverage of the scan tough or impossible. This is where software comes into the picture to enable hole filling etc. I filled in some areas in Aspire that were part of the injection molding process and not necessary for the wood variant. Some of the features on this part were very tiny, such as the little alignment bars at only 0.018" thick, which luckily didn't snap off while machining!
Once the data was ready for digital fabrication, each half was brought into Aspire. Rather than use the data as-is, I elected to add a little flair to one of the case halves using the 3D tools in Aspire. A few lines and a cross-section and a lovely little weave was added for no additional machining cost. Each half was toolpathed and setup to run on the ShopBot. Each half was machined on 2 sides in maple (color doesn't match on them...I just used scrap I had laying around in the shop). I roughed out with an 1/8" and finished with a 1/16" ball. I drilled the screw holes by hand because I wanted to test fit them - but could have done this on the Bot as well.
When machining was complete, I test fit the ones off the machine with the corresponding plastic original. It was a *perfect* fit!!! No file or Dremel work! Now I don't care if any of you are not impressed by this, but I sure am!!! I wanted to seal the halves before moisture warped them, so I put some Watco oil on each half to seal it. Now, there is a reason they don't make tape measures 100% out of wood. If you look at one of the pics, you'll see that the forked mandrel that holds the spring for the tape retraction is glued...I tried to keep it from twisting and snapping, but it just couldn't handle the stress/twisting. I had to glue it. While gluing it (Q-Bond) a little dripped on the tape roll and locked it in place - so the tape won't go in & out now - but that's OK. ALL of the original hardware fit right onto the wood one perfectly. The little detent switch that locks the tape glides effortlessly.
Using the same data, I filled in all of the holes and 3D printed it in plastic. Due to time constraints I just printed the whole thing out solid (20% in-fill) to show how the same data can be used in other ways...So once you invest in 3D data, it's the gift that keeps on giving. You can use the original to make duplicates, or add a little flair to the project. It is also possible to use the data for 3D visualization or to make derivative works to stretch the product line with a similar motif etc.
-B