Desktop ShopBot

[ron_moorehead]

Well I bought the Desktop unit that was on sale in the forum this last week in Seattle. Now all I have to do is find room in the shop to put it.

Has anyone come up with a vacuum table design for the desktop unit yet?

[Brady Watson]

It wouldn't be too hard to do...However it may take a little out of the box thinking to plumb it.

-B

[QUICK-BURN]

Brady, I know you have made some great vacuum tables and vacuum enclosures for the larger shopbot tables. I'm willing to prototype one for my new desktop machine if I can get some help sizing or at least figuring out what the vacuum needs are.

[Brady Watson]

Ron & Richard - What are your vacuum needs? What will be creating the vacuum? What's your budget? What range of parts will you be cutting while using vacuum?

-B

[QUICK-BURN]

For me it's more the criteria, not the budget. I do signs mostly but occasionally a smaller part like 2 " X 2". I've been thinking and would liek to make the 18" X 24" table into 4 or 5 zones that I can select independently that way I can provide maximum vacuum to just one zone if needed.

[Brady Watson]

Richard,
You're not really going to get more than one big zone unless you want to get really complicated or machine into the table itself for little or no advantage over a single zone. You can eliminate a lot of headaches with zones by upsizing your vacuum pump/source.

The attached illustration shows an easy, cheap and reliable way to get vacuum on your desktop. It shows a 2" hole that needs to be fed by your vacuum source, but it can be any size you want. Put a 90 deg elbow or Vac hose right into the hole (Use 2.27" hole for a Fein) and you're ready to go. Perspective is obviously looking up isometrically from underneath the tool.

http://i772.photobucket.com/albums/yy8/braidmeister/DesktopBradyVac.jpg

Once you have the system going, you can cut smaller parts with my Vacuum Film (http://talkshopbot.com/forum/showthread.php?t=11481)method.

I'll leave it up to you what material you choose for the backer and how it attaches to your machine table & plenum/bleeder.

This kind of setup is also ideal for larger ShopBots where you want to make your own 'pods' for holding down dimensional lumber or use vacuum masks. You can use vacuum air directly (flip grid over - with no backer) or machine the whole deal out of composite lumber...the possibilities with vacuum are nearly limitless.

-B

[QUICK-BURN]

I have a Becker SV 5.130/2 pump, do you think this would work for the desktop vacuum table?

[Brady Watson]

I have a Becker SV 5.130/2 pump, do you think this would work for the desktop vacuum table?

Help me help you...List specs: CFM, Hg" or H2O" and HP

-B

[ron_moorehead]

I am out on the road this week and will be at a quilt trade show next week. Once I get back I will start working on a vacuum table for the desktop in looking at the forum I see some vacuum table were shown at the camp in Tulsa OK I need to see some photos from the camp. I plan on using a vacuum motor most likely from lighthouse and most my stuff I cut is senta and I don't cut all the way through it. I was looking to make just a single zone and if I cut a small part I just block off part of the table like I do on by prt alpha 48 by 96. I have found a few photos all ready on the web of a vacuum plunum for the desktop. Will share more once I get back and start on it.

[QUICK-BURN]

Maximum air flow: 55 CFM @Atm. Pr
Maximum Vacuum: 45 in H2O
Maximum Pressure: 47 in H2O
Motor Capacity: 0.6 HP

[michael_schwartz]

45" H20 is about 3.31" HG which is too low.

7"-10" HG is going to be the bare minimum that you would want to work with.

[Brady Watson]

Richard,
An 'on sale' shopvac has more suction & airflow than the pump you have listed...That pump is not suitable for CNC work. I would not even waste your time hooking it up.

-B

[QUICK-BURN]

Thanks guys, really appreciate the help. Can you reccomend one, as long as it's not too expensive I'd liek to buy one just for this purpose.

[Brady Watson]

Do a search for the Lighthouse motors on here. You can probably get a lot of info from Gary's 'Black Box Vacuum' and put yourself together something with enough CFM & suction for around $100 or so. Be sure to get a vacuum gauge and rig up some type of filtration.

-B

[QUICK-BURN]

Are there any advantages to the LH6765-OD-220 over the LH7123-13? Looks like only 1.3 Avg sealed vac, 7.5 Avg CFM 2", and an extra $30.. Do you think i'll need more than two motors on a desktop machine? I'm assuming the best place to order them from is the link in one of the other threads.

http://www.centralvacuummotor.com/shopbot.htm

[Brady Watson]

NO - not much difference other than making it easier to wire on multiple units (240v). The 110v version is more than enough for your little desktop - but keep in mind that there are limits to what vacuum can hold down, which is why not everyone has a vacuum setup. The key is to come up with a setup that you can easily remove so that you can use your t-slots or screw stuff down etc. The system I show above will do that...

-B

[michael_schwartz]

I am using the 120v LH6765-13

Use the 240 volt motors if you can. I would call Ward, at lighthouse and ask about the differences of the OD motors.

I am using two motors on a 4x8 table, with a 5 zone plenum. My smallest zone measures 2'x2' which is about the size of a desktop.

Given the size of your table, one motor would work pretty well and should be more than enough. I don't think two would be overkill if you really wanted to go that route. Especially because you can put a check valve on each, and run either the first or second while allowing the other to cool, during long files.

[michael_schwartz]

Here is a short video clip, I shot this afternoon.

In the video I cut out a 4x4 square of 3/4" baltic birch from a 9"x11" blank. I masked off one of my zones to about 24x18 to simulate the table on a desktop.

http://youtu.be/18Xjfe4jrE0

[QUICK-BURN]

Very nice, I think 2 motors is the way to go even if I cycle them for longer run times to keep them cool or when I am doing a fance carve job and for smaller parts. I tried to get ahold of Ward today but he is out of the country. I'm definitely going 220v but was looking to them to reccomend wither the standard or the OD motor.

[michael_schwartz]

One motor would probably be more than enough most of the time which is something to consider if cost is an issue, and you can always add a second later on if you find you need it. Personally, I would use two, just for the heck of it as long as cost isn't a big deal.

I would try to keep things simple for the sake of getting up and running. You probably won't need allot of plumbing, and the brady vac method is a really easy way to do this. The most important part arguably is going to be finding the ultralight MDF. Specifically Trupan, is the brand name you want to look for, if you can find it.

I spent as much on the material for the cords, and other electrical parts as I did on the motors themselves. Between all that, and the metal enclosure I built for the motors and the cost of an electrician to hook it all up, I came in around or slightly above the cost of a pair of Fein's, without plumbing. That is with better preformance, and when it comes time to replace the motors, that will only cost $250.00 instead of another $800-1000.00.

[QUICK-BURN]

If I monitor the outlet of the Lighthouse motors with my PLC what temp would be a safe limit?