[Hack]

I finished my CNCRP machine a few months ago and have been pretty pleased. I still have some fine tuning to do, but the more I run it and tweak it in, the better it gets. I primarily use my machine for cutting sheet goods and until now I have been screwing the sheets to the table to hold them in place. I use Cut 2D to generate code and place tabs for holding the parts during cutout. While the tabs are nice, they add a step to the handling process vs being able to cut through the material. Also, with the screws holding the sheets down, it has been nearly inevitable that I hit a screw every now and then, trashing both the part and the bit. The bits I use are about 45 bucks a piece so couple of instances of this and I am well on my way to paying for a vacuum table for holding down the parts.

I am planning on a 2 vacuum system divided into 4 zones. Most of the design is not original as I am spending my time sponging off the Shopbot forums for ideas.

So, the first step was to strip the existing table off the machine, down to the bare extrusion. I layed out where I wanted the pvc piping to protrude the base from below and marked them with a simple +. Using a 3" hole saw and a corded drill, I drilled 4 thru holes. This allows a slightly oversized hole for alignment purposes.

While I hade the table top off, I made a diagram of the extrusion to plug into my cad software for drawing the table which I cut with the cnc when the time comes.

The first step doesn't look like much, but the planning and layout is everything in a project like this.

[bobmagnuson]

Interesting! I'll be watching this closely!!!

[Frankmali17]

Good Luck,
Please show us as many details of the planning and process, as I also have some ideas I'm learning from ShopBot, and I'm looking to build the CNCRP Pro machine.
thanks

[ahren]

Hack,

Looks really interesting, and a vacuum table is something I've wanted to put some engineering time towards for a while. Are you planning on multiple chambers, or are you going to use vacuum check valves? I'll certainly be watching to see how this goes!

Ahren
CNCRouterParts

[Hack]

A bit more progress to show.

I put the first layer down on top of the extrusions to create the table using 1/2" MDF. I probably should have used something more stable like plywood according to some on the Shopbot forums, but hey it's what I had. I went with the 1/2" to allow for clearance for the x axis bearings. 3/4 was to thick. This first layer is screwed solidly to the extrusions. The second layer is a pc of 3/4 x 49 x 97 mdf and is glued to the first layer. I will be routing the vacuum channels into this second layer, thus not wanting any screws. I used as much weight as I could find laying around to help hold in place until the glue dried. Once dried, I gave it a skin with a spoilboard bit to level it out.

As far as plumbing goes, this first iteration will simply be the 2 vacuums hooked up to a manifold with 4 ball valves to control each zone. As i get more experienced building vacuum tables or determine by needs change, I may rework it, but for the first attempt that is all I am planning.

Thanks to all to watching.

Dan

[Hack]

After allowing the table to set up and dry, I took the time and surfaced it so it is flat and true to the gantry. I usa a 1.5" mortising bit so it doesn't take to long. Not real pleased with the quality of cut on mdf, but it does the job. I surface at 400 ipm at about .010" deep. You can see the black marker lines on the mdf sheet to be sure I got it all.

I also got the table drawn out in TurboCad, and programmed the toolpaths in Cut2D. A preview image is attached.

I cut the slots (channels) with a 1/2" bit 3/8" deep. See the pictures below for the results. As you can see in the last picture, perhaps I should have used a sharper tool or perhaps a downcut bit. Anything to help the fuzz.

All i can say is that after cutting this, I officially hate cutting mdf. Even with the dust collection going, dust got everywhere. Time to reevaluate the system

[aarggh]

Although the dust with MDF can be quite fine, if your dust extraction is struggling with that, it will be the same for any other materials you cut.

There should be enough vacuum that 100% of the debris is sucked up, if it isn't, then look at the design of the dust shoe, the pipes, or even the vacuum used.

cheers, Ian

[Hack]

Yeah, kind of thought that as well. I have a 1300 cfm grizzly unit that I feel should be more then sufficient. It has a 6" inlet that is seperated via a "Y" into (2) 4" inlets. I have one of the segments going to the router and the other going to "the rest of the shop" That section has blast gates at each tool, that do not seal very well so I think that there is just alot of vacuum loss with that. I already ordered a couple of other (better, I hope) blast gates to shut off each section of the "Y" at very close to the collector and not at the end of the runs by the machines. I think this should help alot with the loss of vacuum. If not, i will disconnect the rest of the system when the router is in use and run it direct.

Got a small start on the manifold / piping. Teaser picture below. I ordered thesr ball valves off of EBAY for a few buck a piece. They are 2" PVC.

Dan

[Hack]

over the past few days I got the mdf sealed using 3 coats of polyurethane. The next thing will be to add the sacrificial spoilboard. Perhaps even bigger to me was figuring out the dust collection issue. 3 things were contributing to the issue. First. I added the additional blast gates. I can now section off the system and have only the side with the router drawing when I use the cnc. Secondly, I found a bit of a birds nest in one of the pipe elbows causing a bit of blockage. And last, but not least, I replaced the brushes on my dust shoe so they are now making a better seal while routing. Not sure which of the 3 things made the biggest difference, but it now draws like it should and I have significantly less dust.

Not much other progress....been busy staining my deck.....yippee!

[Hack]

Well now that I have finished staining the deck and getting a coat of wax on the car before winter gets here, I have been able to start working again on the table. I finished building the manifold as well as designing a board to attach to the end of the router and hold the manifold in place. Probably not really necessary, but it was easy enough to do. Nothing real fancy, just a diagram to show which ball valve controls which zone and of couse the corresponding numbers below each valve. I cut the board in 2 sections so that 1 is removable allowing access under the table.

I also ordered the 2 vacuum motors tonight. I got them from here I ordered the 116765-13 models

Below are some additional pictures for your viewing pleasure.

Thanks for watching

Dan

[Frankmali17]

Hello Hack,
It looks very interesting.. .I wish you lots of success...
What are you planning to use as your source of vacuum?

[tinygiants]

I also ordered the 2 vacuum motors tonight. I got them from here I ordered the 116765-13 models

Below are some additional pictures for your viewing pleasure.

Thanks for watching

Dan

I am not the author, but I believe this is what you are looking for.

[Hack]

I recieved the motors the other day and have been designing a base to mount them to. Hopefully I will get them cut this weekend. I am trying to figure out how I am gonna connect the motors to the 2" pvc for the vacuum table plumbing. The inlet on the motors is approx 1.88" in diameter. Metal at that. Not sure what I can use for an adapter. Any suggestions?

Thanks

Dan

[bobmagnuson]

Take a look at any of these ShopBot threads and see how they did the motor box...

Black Box Vac Source - Let's Talk ShopBot
Twin Series Parallel Vac Motor Setup - Let's Talk ShopBot
The QUAD - Let's Talk ShopBot

[Hack]

I have taken a look at those threads a few times before and never saw mention of a specific item / part number that was used. Thanks anyways. All for naught though as a trip to Home Depot this morning solved my issue. They had exactly what I needed. It is a flexible coupling that reduces from 2" pvc to 1.5" pvc. Fits perfectly.

Other progress included getting most of the table plumbed. I just need to connect the under the table piping to the manifold and the table piping will be done. Next item on my agenda however is to build a mount of sorts for the motors and bolt them under the table.

I have also been working on installing a separate circuit in the work shop for the motors. I didn't want to run them on the same breaker as the computer and control box for the cnc. If the vacuum were to blow the breaker, I would not want it to also ruin a part I am working on by tripping the control computer, router, etc at the same time. I also did not want to put it on the same circuit as my dust collector as I thought that would be to much.

Enjoy the pictures below.

Dan

[Frankmali17]

Hello Hack,
Your design and the postings looks very good so far, thank you for your postings.
I may be wrong, but from what I saw the Shop-Botters doing, the port you connected to the PVC pipe is actually the exhaust port....
If that is true, that may be the opposite of what you are actually trying to achieve.
I hope it all works out.

[bobmagnuson]

Good catch! The intake is at the bottom of the motor, hence the reason the Shop-Botters gang mount them in a box.

[Hack]

Hmmmm. Wow, uuuuggggghhhhhhh! Boy do I feel stupid. Thanks for the catch, it is greatly appreciated. Hopefully I do not have to backtrack to much with the plumbing. I shouldn't but will definitely have to redesign how the motors are mounted etc. Guess I need to read the shopbot threads a bit closer.

Dan

[Frankmali17]

Hey Hack...
If you look at a few threads... you will find some ideas on enclosures that the motors can sit in, and act as a plenum and quiet things down a bit...
How you had a chance to use the machine to do much cutting? or did you go right into making a vacuum plenum?

Good luck.

[Hack]

I have had the machine completed for few months or so, and have done about 10 kitchens with it. Mainly cut cabinet boxes.

I made a bit more progress today. Got the box made to hold the motors. Only thing I have to do is to make cutouts in the lid for the exhaust and also wiring. I will also add a filter to the motor cooling fan to keep it from sucking in debris.

The first couple of pictures are of the parts on the cnc. The rest are assembly pictures.

Dan