Vacuum Mounts - inspired by Improbable Construct

discussion of design changes / improvements / suggestions
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Tom Smith
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Vacuum Mounts - inspired by Improbable Construct

Post by Tom Smith » Mon Jun 11, 2012 1:03 am

I was inspired by the mounts that Improbable Construct rigged up, and wanted to make a mount that I could easily attach/remove the vacuum hose from, so I came up with this:
Dremel mount with vacuum-3d-1.jpg
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Dremel mount with vacuum-3d-1.jpg (231.26 KiB) Viewed 4247 times
The pipe is all 3/4" Schedule 40 PVC from the local hardware store - one 45 degree elbow on the bottom bracket, one straight coupler on the top, and a short length of 3/4" pipe in the middle. I figure that I can either friction fit the elbow and coupler to the spindle clamp, allowing for the nozzle to be adjusted somewhat, or I can glue them to one of the clamps for additional rigidity. The top I left alone for now, as if this proves valuable to others, it would be up to the implementer to determine what manner and size of adapter for their own vacuum would be necessary.

So, what do you all think? Is this something that could work? Are there improvements that people can suggest? As I am still anticipating the kit, this is as much an exercise in learning Sketchup as anything else. I plan on trying to generate the g-code for the mounts and running it through CNCSimulator as well.

Tom
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edwardrford
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by edwardrford » Wed Jun 13, 2012 3:23 pm

I must be a slow learner or something. The first time I looked at your picture Tom I couldn't figure out what it's intentions were.

Today I came back into the thread to delete that last reply (I thought it was spam because of the user's signature to 'business voip systems') and re-looked at your original posting.

I see exactly what you're doing now. Instead of running the vacuum hose all the way to the bottom, you created a pre-mounted attachment made from PVC, and would connect the vacuum to the top of the PVC attachment. I can see how this would have it's advantage over running the hose all the way down to the bit, as your flex point would be higher, probably greatly reducing the tendency of the hose to 'pull' on the gantry.

I like it a lot. Can you create 2D DXF files from your sketchup sketch so I can import them and give it a try? Or better, can you zip your sketchup sketch and post it to this thread?

-Edward
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
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Tom Smith
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by Tom Smith » Wed Jun 13, 2012 6:23 pm

edwardrford wrote: I like it a lot. Can you create 2D DXF files from your sketchup sketch so I can import them and give it a try? Or better, can you zip your sketchup sketch and post it to this thread?

-Edward
Hi Edward,

I will upload it when I get home later tonight. One thing to keep in mind that due to variation in outer diameter of the PVC fittings, you might want to resize the holes to fit the pipe diameter available to you.

Tom
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edwardrford
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by edwardrford » Wed Jun 13, 2012 6:34 pm

I was considering doing just that. However, I've found that by cutting a slot on one edge of the hole, and running a bolt through, you can accommodate a wide range of sizes.

The original UHMW spindle mount is a good example of that. The slot gives you a little bit of 'squeeze' if the hole would be too big, and a little bit of flex if it's too small. I will probably dimension the hole to the standard size pipe (lets say 2"), and then cut a 1/8" slot to accept the tolerances.

-edward
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Shapeoko 2 #0 - a couple of upgrades.
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Improbable Construct
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by Improbable Construct » Wed Jun 13, 2012 8:45 pm

Sorry I didn't reply back on this earlier. I think the concept is great. I have wanted to grab the hose off the mount many times for spot clean ups or at the end of the job. My problem with the whole setup has been that when you get the end of the hose far enough away to not hit the work surface it doesn't do a very good job. It grabs MDF dust and keeps it out of the air but for Acrylic and HDPE the pieces go flying everywhere and the vacuum grabs very little of it.

I am thinking that for a side draw mount, it needs to be mounted to the X axis plate free from the Z axis. This way the height of the vacuum could be set to just clear the work surface and the bit can move up and down in the work piece independently.
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Tom Smith
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by Tom Smith » Wed Jun 13, 2012 8:52 pm

Improbable Construct wrote:Sorry I didn't reply back on this earlier. I think the concept is great. I have wanted to grab the hose off the mount many times for spot clean ups or at the end of the job. My problem with the whole setup has been that when you get the end of the hose far enough away to not hit the work surface it doesn't do a very good job. It grabs MDF dust and keeps it out of the air but for Acrylic and HDPE the pieces go flying everywhere and the vacuum grabs very little of it.

I am thinking that for a side draw mount, it needs to be mounted to the X axis plate free from the Z axis. This way the height of the vacuum could be set to just clear the work surface and the bit can move up and down in the work piece independently.
Hi IC, I thought that with this setup, given that the elbow at the bottom is made to fit standard PVC pipe, a short length could be added to extend the nozzle towards the bit. in fact, with a little creative cutting, the nozzle could be placed so that it envelops the bit completely. This may be impractical, but it looks good in my imagination :)

One other consideration is that with most bits, material is ejected in a pattern - ie. more shoots out one side than the other. At least, I observed this when working with a table mounted router. Therefore, by orienting the intake nozzle in the appropriate area, more detritus may be cleared.

Of course, I have to imagine all this, as my kit isn't due to ship til tomorrow, but I appreciate the input from you experienced members, and hopefully I can incorporate it when I do build it!

Tom
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Improbable Construct
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by Improbable Construct » Wed Jun 13, 2012 9:13 pm

Tom,

The problem is that the the spindle moves up and down and therefor the vacuum does as well. So if you are going to cut a shape out of some 20mm thick material the vacuum has to start at the very minimum 20 mm off the work surface. It will likely have to be closer to 25mm because you really don't want to crash the vacuum into your work. This means the the vacuum doesn't work very well at the start of the cut and by the time it gets close enough to have good suction your cut is already packed full of chips and dust.
I thought the same thing about material ejection, but on a mill it tends to eject opposite of the direction the bit is cutting. Since the mill cuts in any direction the chips are ejected in many directions. Ideally the vacuum would be able to hug the back of the bit no matter what direction it was going.
Shapeoko #Classified some of the bolts may be original parts.
Shapeoko 1 # ???? Stainless plates, still in the box.
Shapeoko 2 # 3926 not stock
Shapeoko 3 # 0003
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Tom Smith
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by Tom Smith » Wed Jun 13, 2012 9:31 pm

IC - I guess this is the reason people create a skirt around the bit. It serves to constrain the area that the debris can travel to, and provides a concentrator for the suction of a vacuum.

So the hose application that you are using must have some of the same issues, I guess? Have you considered further enhancements to improve the operation? Perhaps a skirt is inevitable...

Tom

Edit: I see the brush ring you linked to in your post :) again, that'll teach me for not RTFM'ing :)
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Improbable Construct
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Re: Vacuum Mounts - inspired by Improbable Construct

Post by Improbable Construct » Wed Jun 13, 2012 9:50 pm

My setup actually works great for grabbing all the tiny dust particles when I was milling MDF.
Where it fails: deep cuts, plastics, and large chips.
It is still better than following the bit around with a vacuum by hand!
I am working on a dust shoe with a brush strip.
It is a lot harder than I thought it would be.
Hopefully I will be able to work on some new revisions this weekend.
Last edited by Improbable Construct on Thu Jun 14, 2012 3:27 am, edited 1 time in total.
Shapeoko #Classified some of the bolts may be original parts.
Shapeoko 1 # ???? Stainless plates, still in the box.
Shapeoko 2 # 3926 not stock
Shapeoko 3 # 0003
Store:
http://ImprobableConstruct.com
Twitter:
https://twitter.com/ImprblConstruct

Tom Smith
Posts: 297
Joined: Mon Apr 09, 2012 9:55 pm
Location: North Vancouver, British Columbia

Re: Vacuum Mounts - inspired by Improbable Construct

Post by Tom Smith » Thu Jun 14, 2012 2:47 am

Here is a zip containing sketchup drawings of the mounts pictured above. I still haven't managed to get gcode for the simulator, so hopefully the models aren't fubared in some way or another ;)
Attachments
Dremel mount with vacuum.zip
(15.44 KiB) Downloaded 165 times
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