Vacuum table Setup Advice

[andy_con]

im after some advice on vacuum pumps for a vacuum table setup.

i want to do exactly this -


http://youtu.be/jDrRICZq4KQ

no idea if its the right sort of table, but been looking at this table as its the perfect size for my mill

http://vacuumtables.co.uk/product/vacuum-table-vt3020-gr/


would this pump do and im assuming im going to need a liquid seperator as my mill has flood coolant?

http://www.ebay.co.uk/itm/Robinair-RA15601-Cooltech-Vacuum-Pump-240-110v-/271952150983?hash=item3f519c81c7&clk_rvr_id=886038514721&afsrc=1&rmvSB=true

thanks

[Boyan Silyavski]

I think it should work. A friend has similar size pump and the plate you aim to use is fairly small.

[andy_con]

ok thanks

im assuming as im machining all the way through a vac-mat will be better as it wont suck as much coolant in and a proper holed matt?

https://www.hoffmann-group.com/GB/en/houk/Clamping-technology/Magnetic-clamping-technology/VAC-MAT-mats-1/p/385040

[Boyan Silyavski]

It will not suck dust and metal, that's for sure, due to the micro holes. It will hold steadier also, due to friction.

[andy_con]

It will not suck dust and metal, that's for sure, due to the micro holes. It will hold steadier also, due to friction.

how does it work with a normal holed mat? does the table suck metal into the pump?

(sorry ive never used a vacuum table before)

[Boyan Silyavski]

Depends how fine is the sucking hole. Not the vacuum hole you see on pictures 3-6mm, but the real sucking hole in the vacuum hole center, it could be 0.5-1mm . Its a good idea the vacuum table to be made from 2-3 pieces and that could be dismantled for cleaning or repair.

http://www.mycncuk.com/attachment.php?attachmentid=15901&stc=1

The vacuum table from the first link was ok and they have mats. any mat from superstore 2-5eur per meter will do the job, some experimenting is needed. cause they sell ridiculously expensive the mats.

Or just DIY around the vac-mat

[andy_con]

anyone know anything about these pumps?

http://www.mastercool.com/product/90066-a-6-cfm-vacuum-pump-single-stage/

seems fairly decent, says its designed for continuous use, there are many brand new ones on ebay so am rather tempted

I'm assuming 6cfm will be enough power?

[andy_con]

been trying to do a vacuum table setup but an failing badly.

I purchased this -

http://www.ebay.co.uk/itm/CNC-Vacuum...item487aa50799 (http://www.ebay.co.uk/itm/CNC-Vacuum-Bed-table-VT-A4-milling-clamping-engraving-/311295281049?hash=item487aa50799)

and today I got the uni-jet 75

http://www.cattaniesam.co.uk/suction...ry/uni-jet-75/ (http://www.cattaniesam.co.uk/suction-systems/multiple-surgery/uni-jet-75/)

the guy from ebay recommends 3cfm, if I worked it out correctly the uni-jet does 1250L/min which is 44cfm. so in theory plenty of suck.

got a 32mm pipe coming out of the vacuum pump, then just before the table reduced down to 10mm as that's what you need to plug into the vacuum table. length of pipe maybe 2 metres

when on and you try to move the work piece with your hand, you can but its bloody hard, its stuck down pretty dam well. you have to really really force it to get it to move with your hand. but when trying to machine it, it seems to move so easily.
I'm using a 6mm cutter, with a z depth of -0.5mm with a feed rate of 300mm/min

anyone got any advice?

[Boyan Silyavski]

UNI-JET 75Max. vacuum level: 140mbar (continuous service)

Are you sure you have got the right pump?

you need ~25 Inches Hg which is around 850mbar vacuum

My air compressor at home pulls on the inlet 0.94 bar =~ 940 mbar =705.05993009406 mmHg

Your pump is way off, it seems.


Who told you to look for CFM? you dont have 4x8 machine where you need 20HP pump with CFM rating.


Unscrew your air compressor/ what ever size, 1-2hp is ok/ inlet filter and connect the vacuum table and check what i am talking about. Dont worry about the continuous use, nothing will burn. In fact it runs cooler. Temperature rises from compression, not suction. If your compressor is newish it will make damned good vacuum.

[andy_con]

Ok, so I have the wrong pump?

Not sure what you mean by


you need ~25 Inches Hg which is around 850mbar vacuum

What's an air compressor got to do with a vacuum table

Sorry I don't fully get your reply

[Boyan Silyavski]

i am saying that the job could be done by any 1-2hp air compressor with or without additional expansion chamber. which cost for 2hp ~70 euro at any home depot.

so you can hook the compressor and check if you have all right, cause with the compressor should work Ok without any problem.

what i am saying is that a typical air compressor pulls 6x more the vacuum compared to the pump you have bought

[Boyan Silyavski]

please read that thread http://www.mycncuk.com/threads/8294-DIY-Vacuum-Fixtures

[andy_con]

I don't understand how you can use a compressor, but will take a look at that other thread at lunch.

A compressor blows air, not sucks air

I only have a small compressor

BB24D:


http://www.bambi-air.co.uk/uploads/files/2015/06/Budget-Range.pdf

[GEOFFREY]

For a compressor to compress air it must first suck the air in through the inlet filter. If the inlet is blocked or choked it will pull a vacuum. Boyan has suggested trying to use that vacuum to operate your vac hold down. that would be a very simple and cheap (free) way to check if the system works. Good luck. G.

[andy_con]

Ah now that makes perfect sense thanks.

When you say the system works, I know the table and bits work as work peice does get held down just not strong enough.

I'm assuming you wpuld only use a compressor to test not as a final solution as the compressor would need to be running for an hour straight to draw a vacuum whilst you do the machining?

[Boyan Silyavski]

Ah now that makes perfect sense thanks.

When you say the system works, I know the table and bits work as work peice does get held down just not strong enough.

I'm assuming you wpuld only use a compressor to test not as a final solution as the compressor would need to be running for an hour straight to draw a vacuum whilst you do the machining?

depends on your priorities. yes, i suggested to test it using the compressor which makes perfect hold down.

having in mind a compressor on a boot sale is 20-30euro or brand new is 70-80euro, who cares if it will last an year or 2. electricity price and noise are the only real life concerns. people have reported compressors running like that more than an year without any problem. as i said before this is much more easy for the compressor than to compress.

[andy_con]

ok ill give it ago, thanks

ive never in my life seen a compressor that cheap. mine is a silent one and new its about £400-500

just about to read that other thread you linked to.

with the current uni-jet vacuum pump i purchased, how important is size of pipe? should i be aiming for big or small piping to the vacuum table?

[JAZZCNC]

The other option if you have a good compressor is to use a Vacuum generator and pull a vacuum into a cyclinder.
This way your not stressing the compressor motor or if usiing the Compressor tank has the vacuum reservoir risking the chance of Compressor tank imploding because it's not designed for vacuum.

Also you don't say how small the part is your trying to hold.? Small parts are difficult to hold due to less surface area so you may need a dedicated Jig with better Vacuum seal to maximise the pull down.

[andy_con]

My compressor in very big so probably couldn't do that

Work peice was 100 by 120 mm

[JAZZCNC]

My compressor in very big so probably couldn't do that

Work peice was 100 by 120 mm

Couldn't do what.? Was you referring to my suggestion because Big is good when it comes to a vacuum generator.
The cyclinder doesn't need to be massive just strong to handle the vacuum. Your only creating a reservoir of vacuum to help with the intial suck down and to save the compressor or vacuum pump from running all the time.

Like a Compressor has Preassure switch you can get a Vacuum switch that does the reverse and switches on when vacuum drops below set amount.

For small parts like this you don't need high volume but do need High vacuum pressure so a small tank pulled down to high vacuum will work. With small part like this you will be better with sealed around the part setup rather than pulling a whole area of a plate which will waste some vacuum.
That Vacuum fixture plates is ok for wood and larger pieces that fill most of the area but for best hold down you'll be better with grid system and seal just the area your using.

[Lee Roberts]

My friend Ralf use's one of these pumps http://m.ebay.co.uk/itm/271844104827 for his diy vacuum system quite successfully, below is the build video from his youtube channel:

https://youtu.be/viVbB5mzSaw

There are some other videos there too, detailing his machine and the vacuum setup.

.Me

[JAZZCNC]

What your cutting also plays a big part here.!
That setup Lee linked to is great for wood etc with larger area and he's made a cracking job of it. But with small parts and high cutting forces on material like Ali or steel then it would struggle I reckon.
It's horses for courses really. If your cutting hard materials then you'll need good well sealed high vacuum and/or select your cutting parameters carefully.

[andy_con]

am I right in saying all I do is connect the vacuum table to where the compressor sucks air into to fill up, open the oil drain value (which releases air from the compressor) turn the compressor on and it have suction?

I just need to find a good balance between the amount of air coming out of the compressor and the amount being sucked in?

so would something like this do

http://www.ebay.co.uk/itm/SILENT-TYPE-COMPRESSOR-OIL-FREE-AIR-/221860578241?hash=item33a7ebc3c1


Couldn't do what.? Was you referring to my suggestion because Big is good when it comes to a vacuum generator.
The cyclinder doesn't need to be massive just strong to handle the vacuum. Your only creating a reservoir of vacuum to help with the intial suck down and to save the compressor or vacuum pump from running all the time.

Like a Compressor has Preassure switch you can get a Vacuum switch that does the reverse and switches on when vacuum drops below set amount.

For small parts like this you don't need high volume but do need High vacuum pressure so a small tank pulled down to high vacuum will work. With small part like this you will be better with sealed around the part setup rather than pulling a whole area of a plate which will waste some vacuum.
That Vacuum fixture plates is ok for wood and larger pieces that fill most of the area but for best hold down you'll be better with grid system and seal just the area your using.

[andy_con]

yeah I'm machining ally and all the way through


What your cutting also plays a big part here.!
That setup Lee linked to is great for wood etc with larger area and he's made a cracking job of it. But with small parts and high cutting forces on material like Ali or steel then it would struggle I reckon.
It's horses for courses really. If your cutting hard materials then you'll need good well sealed high vacuum and/or select your cutting parameters carefully.

[JAZZCNC]

yeah I'm machining ally and all the way through

Well there's your problem doubled then.!! Soon as you cut thru you release vacuum. So even more vacuum is required. IF the remaining area is small you'll need high vacuum to hold onto it.

Really with small parts then vacuum is only any good if you have dedicated jig that will hold full high vacuum in areas of the parts that don't cut thru.

End of the day it's logical if you think about it. Surface area is the key, so if the part is small there's much less area to hold onto so higher vacuum pressure is required to hold it but less volume needed. Large parts have more surface area so a lower vacuum pressure can hold it because there's more to hold onto. Start cutting thru and large area then volume of vacuum required is more but cut too much and at some point the pressure will drop and you'll loose grip.

[andy_con]

this is my goal, datron make it look so easy...


https://www.youtube.com/watch?v=jDrRICZq4KQ

datron make it look dead easy


https://www.youtube.com/watch?v=GNsA70whfoQ

I was just testing with a small bit of scrap ally I had, but what I actually want to machine is 250mm by 160mm by 5mm thick.


Well there's your problem doubled then.!! Soon as you cut thru you release vacuum. So even more vacuum is required. IF the remaining area is small you'll need high vacuum to hold onto it.

Really with small parts then vacuum is only any good if you have dedicated jig that will hold full high vacuum in areas of the parts that don't cut thru.

End of the day it's logical if you think about it. Surface area is the key, so if the part is small there's much less area to hold onto so higher vacuum pressure is required to hold it but less volume needed. Large parts have more surface area so a lower vacuum pressure can hold it because there's more to hold onto. Start cutting thru and large area then volume of vacuum required is more but cut too much and at some point the pressure will drop and you'll loose grip.

[JAZZCNC]

this is my goal, datron make it look so easy...

datron make it look dead easy


Argh.!! . . It's Dangerous watching expensive Pro-level machines because you have a lot of specialised and expensive things there all working together to make it look that easy. Which are not always obvious.!!

First there is a high power Vac pump or system designed to cope with the vacuum loss doing the sucking. The Vac table is a high Density hole pattern table type optimised for holding small parts. Then you have fact they are using special permeable Matt systems like VillMill which has a adhesize layer to help hold it down and distribute suction evenly.
Then quality 60,000rpm spinlde taking relatively small DOC at high feeds rates with quality Carbide tooling connected to a sophisticated cooling system greatly helping ease things along.!

Now I'm not saying milling small parts can't be done but it is a different ball game to larger pieces with more surface area so requires certain methods to be employed. Or Buy expensive Vacuum systems like Datron offer designed to cope with it.!

Can't just throw it on standard table with relatively low pressure sucking directly from the pump then cut thru it or take heavy cuts and not expect it move.
If it was that easy we'd all just use Henry's and Vacuum table for holding every thing.!!

[andy_con]

Im well aware datron stuff is in a different league, I have their price list and know how expensive the kit is



am I right in saying all I do is connect the vacuum table to where the compressor sucks air into to fill up, open the oil drain value (which releases air from the compressor) turn the compressor on and i have suction?


I just need to find a good balance between the amount of air coming out of the compressor and the amount being sucked in? Or buy that digital gage


so would something like this do

http://www.ebay.co.uk/itm/SILENT-TYP...item33a7ebc3c1 (http://www.ebay.co.uk/itm/SILENT-TYPE-COMPRESSOR-OIL-FREE-AIR-/221860578241?hash=item33a7ebc3c1)


How do I work out if a compressor will give me the required suction?


Vacuum tables UK sells mats without holes in, so could this be another possible improvement?


http://vacuumtables.co.uk/product-category/vacuum-table-accessories/adapters-and-mats/mat/

[Boyan Silyavski]

As Dean says- be reasonable.

Now you know, the most important thing is to find the most sticky mat possible. I would go further and say that best result is a combination of screws and vacuum, hence, custom fixture for each part done in quantity. I also have thought to make the sticky thing from casting silicone gasket in shape if necessary

Not trying to sell, but if you have a total of 30 euros to spare, i can send you a slightly used brand pressure switch with digital pressure readout and analogue 5v output, which new goes for around 80-90euro at least. PSA4-102VP (http://online-sy.com/uploads/image/130728124014.pdf). I have 2 of them if sb needs. so you could use it to read negative pressure, switch on off compressor by relay / if additional deposit for vacuum, and so on...

as i said any 1hp-2hp air compressor, take out inlet filter and fit there vacuum hose. Usually 3/8" adapter. Rarely 1/4". At the output fit some connector so the compressor blows out at all time, without switching off. Furthermore a vacuum deposit made from propane bottle could be fitted between vacuum hose and air inlet, plus the switch could stop compressor when desired negative pressure achieved. So electricity is saved.

[andy_con]

ok so mat important, I may have to buy a few and test them. not a problem

screws are a no, if it cant be done 100% by the vacuum table then I wont be doing it. like I say part size is 250mm by 160mm by 5mm thick

id rather have the vacuum table completely separate from mach3. but thanks for the offer.
ok will see what compressor I can find for a cheap price. does the size of the tank on the compressor matter? or is it just the power that's important?

sorry but I don't get the purpose of the propane bottle? do I really need that?


As Dean says- be reasonable.

Now you know, the most important thing is to find the most sticky mat possible. I would go further and say that best result is a combination of screws and vacuum, hence, custom fixture for each part done in quantity. I also have thought to make the sticky thing from casting silicone gasket in shape if necessary

Not trying to sell, but if you have a total of 30 euros to spare, i can send you a slightly used brand pressure switch with digital pressure readout and analogue 5v output, which new goes for around 80-90euro at least. PSA4-102VP (http://online-sy.com/uploads/image/130728124014.pdf). I have 2 of them if sb needs. so you could use it to read negative pressure, switch on off compressor by relay / if additional deposit for vacuum, and so on...

as i said any 1hp-2hp air compressor, take out inlet filter and fit there vacuum hose. Usually 3/8" adapter. Rarely 1/4". At the output fit some connector so the compressor blows out at all time, without switching off. Furthermore a vacuum deposit made from propane bottle could be fitted between vacuum hose and air inlet, plus the switch could stop compressor when desired negative pressure achieved. So electricity is saved.

[andy_con]

would this compressor work for example?

http://www.screwfix.com/p/stanley-8216035scr011-24ltr-compressor-with-5-piece-accessory-kit-240v/48089

[JAZZCNC]

You'll notice I'm not commenting on the Compressor setup and thats because I don't agree with it. Not saying it doesn't work it's just not correct way IMO and just a lottery to when it dies.!.

The better way is to have a dedicated Vaccum pump(or Generator) pull a Vacuum into reservoir tank that is strong enough to hold high vacuum pressure. Fit a Vacuum switch so pump is turned on / off has required. If used with good sealing practises then you'll hold small parts no problem.

The secret really is simply lowering the vacuum loss so often dedicated Jigs or Pods with unbroken Vacuum seal work best or the only way without getting silly on the Vacuum system.!! . . . Mats etc work but only to a point and the cutoff point will depend on part size and size/amount of cut-thru.

[andy_con]

So I'm assuming you would need an in and out for the reservoir tank?

So table in, compressor out (so to speak)

Still not sure I get the reservoir tank, so you just remove all the air from it, so it then wants to pull the air from the vacuum table and acts as suction for the table?

[GEOFFREY]

Just think of the reservoir as a storage system for the vacuum so that there is vacuum available sometimes when the demand would be greater than the instantaneous capacity of the pump. G.

[andy_con]

Ok cool

Are these any good

http://www.clampusystems.com/Venturi.html

Some claim 90% odd vacuum

Not saying they are a perfect solution but are they worth considering if you have a big enough compressor?

[JAZZCNC]

Ok cool

Are these any good

http://www.clampusystems.com/Venturi.html

Some claim 90% odd vacuum

Not saying they are a perfect solution but are they worth considering if you have a big enough compressor?

Yes they work good but again you need a Reservoir tank because they struggle to provide enough volume direct from the generator.
Having reserve of vacuum is what you need for when vac loss happens. Otherwise you need a powerful vac pump.

Just think of it has the reverse of a compressor, you wouldn't try using air tools with no air in your tank because the pump would struggle to keep up with the demand. It's just the same but with negative pressure.! . . . Holes in your work piece are like having a high CFM air tool.!

[andy_con]

fair enough, was just a thought.

I'm tempted to just put a good quality vac pump on my credit card, do it properly first time.

any recommendations on single phase vac pumps?

[JAZZCNC]

fair enough, was just a thought.

I'm tempted to just put a good quality vac pump on my credit card, do it properly first time.

any recommendations on single phase vac pumps?

My advise is speak to someone who deals with Vacuum tables/pumps and tell them what your trying to do because your not wanting simple Vac holding when it comes to small parts with thru holes.

Or better still stand back and look for alternatives to do what your wanting. There will be other less expensive ways.!!

[andy_con]

will do

I know there are less expensive ways but home brew also means faff. sometimes its nice to buy something off the shelf

is 250mm by 160mm small?

[andy_con]

just been doing some ebay searching, I'm guessing this bad boy would solve all my problems?

http://www.ebay.co.uk/itm/Becker-Vacuum-Pump-FK80-2-100T-Ref-V2107-/252085024061?hash=item3ab170353d

[Boyan Silyavski]

I would use the compressor setup to resolve all table, mat and fixture issues. Once i know that all functions and what exactly i need i would buy then the proper sized vacuum pump.

Jumping to buy the first vacuum pump seen is not a good idea. From what i see from the picture you are again on the wrong path.

You need a 2 stage low volume high pressure vacuum pump / but enough volume/ , no high volume low pressure vacuum pump. These are not the proper technical words may be , just to have an idea what i am talking about.

This is exactly the vacuum pump (http://www.ebay.co.uk/itm/Edwards-Pfeiffer-Leybold-Adixen-Alcatel-2010-Vacuum-Pump-/181690689432?hash=item2a4d9be798) my friend bought from ebay. he is using it for a vacuum chamber. I am thinking of buying one also. It seems to me its up to the task as i have seen it in real life. Its a sucker. 7cfm.
Check all specifications again including electrical, ask the vacuum table dealer or manufacturer if its ok and buy that sucker. It will be extremely unacceptable new, just check price :-)

[andy_con]

so that pump you link to on ebay, would it do for what I need is the question?

theres so many figure flying round its hard to know exactly what I need to look for in terms of spec


I would use the compressor setup to resolve all table, mat and fixture issues. Once i know that all functions and what exactly i need i would buy then the proper sized vacuum pump.

Jumping to buy the first vacuum pump seen is not a good idea. From what i see from the picture you are again on the wrong path.

You need a 2 stage low volume high pressure vacuum pump / but enough volume/ , no high volume low pressure vacuum pump. These are not the proper technical words may be , just to have an idea what i am talking about.

This is exactly the vacuum pump (http://www.ebay.co.uk/itm/Edwards-Pfeiffer-Leybold-Adixen-Alcatel-2010-Vacuum-Pump-/181690689432?hash=item2a4d9be798) my friend bought from ebay. he is using it for a vacuum chamber. I am thinking of buying one also. It seems to me its up to the task as i have seen it in real life. Its a sucker. 7cfm.
Check all specifications again including electrical, ask the vacuum table dealer or manufacturer if its ok and buy that sucker. It will be extremely unacceptable new, just check price :-)

[GEOFFREY]

Just to put my twopenorth in. I personally think that if you are cutting small parts in ally, don't bother with trying to use vacuum without some other form of clamping device. Use clamps, jigs, fixtures or whatever, but I think you will waste a lot of time and money with vacuum alone. I also do not believe that you will get away using only a single phase pump. If you are cuttig small parts from a large sheet area, it may work, really vacuum hold down is fsr better suited to timber/board type products. Anyway, good luck, but don't wastew too much time, effort or money. G.

[JAZZCNC]

Just to put my twopenorth in. I personally think that if you are cutting small parts in ally, don't bother with trying to use vacuum without some other form of clamping device. Use clamps, jigs, fixtures or whatever, but I think you will waste a lot of time and money with vacuum alone.

Agree 100% Geoffrey.!! .

[andy_con]

How is 250mm by 150mm small?

[JAZZCNC]

How is 250mm by 150mm small?

It's not untill you start cutting thru it.!! . . . Just like a parachute works fine when canopy is inflated but punch a few holes in it and you'll reach mother earth much sooner than you'd like.:angel:

[JAZZCNC]

How is 250mm by 150mm small?


What is it exactly your wanting to cut and how many and size of holes/cutouts.?

[andy_con]

no word of a lie exactly this


http://youtu.be/jDrRICZq4KQ

I machined this case in separate panels, it took forever. so I want to machine these panels but on a vacuum table

http://i187.photobucket.com/albums/x202/magicmushrooms1/250mm%20projector/DSC_6129_zps193d5a35.jpg

[JAZZCNC]

Not sure why that would take for ever and certainly doesn't need a vacuum table. Those panels would take minutes using conventional hold down methods.!
Couple of intial clamps until few holes drilled then screw it down and carry on. Simplizzzz

[andy_con]

yeah so square up on the table using a test dial.

clamp

drill some holes

remove and fix down to a jig

put back in mill and re-square using test dial

machine the rest.

or put straight onto a vacuum table and do the whole thing in one go

[JAZZCNC]

yeah so square up on the table using a test dial.

clamp

drill some holes

remove and fix down to a jig

put back in mill and re-square using test dial

machine the rest.

or put straight onto a vacuum table and do the whole thing in one go

No no your making it far more complex than needed. If one off then just have base board you can screw into. Clamp it down do the first op which is drilling cycle then stick a few screws into it. Remove clamps and carry on with rest of the cycle.

If got lots of same to do then do the same but with permantent fixture jig with toggle clamps and holes already in to accept threaded bolts.

Standard stuff really and not complicated or timely.!

[andy_con]

meh still not as good as a vacuum table ;-)

[JAZZCNC]

meh still not as good as a vacuum table ;-)

Well all can say then is you got too much bloody money. . :joker:

[andy_con]

haha if only...

I like to do thing properly first time, sometimes DIY just isn't good enough.

ive got a tormach touch probe, z height setter, tapmatic tapping heads, threadmills the lot. I like to just do it properly

[Neale]

DIY vacuum might be a bit more tricky, but I don't see how an expensive high quality vacuum system overcomes the biggest resetting issue which you have already mentioned in passing. What's all this nonsense about clocking each piece? Clamp down the spoil board, then use the router to drill holes for locating pins. You'll surely do something like this with a vacuum hold-down? After that, it's difficult to believe that toggle clamps are much slower than vacuum. The difference in cost could go to some really nice cutters, which might even reduce the cutting time by more than the difference in clamping time!

[JAZZCNC]

haha if only...

I like to do thing properly first time, sometimes DIY just isn't good enough.

ive got a tormach touch probe, z height setter, tapmatic tapping heads, threadmills the lot. I like to just do it properly

Ye I know what you mean but this isn't DIY technique it's the way it's often done in industry. Vacuum isn't widely used for small parts and those with lots of thru holes and thats for a good reason.! . . . It's very very expensive to do correctly and can be unreliable. Fixtures and Jigs work and are repeatable time after time..!! . . . Like this.!!

How well do you think your standard vacuum system would do with holding this down with so many cuts and a deep depth of cut.?


https://www.youtube.com/watch?v=gitIQ0xnFUg

[andy_con]

is that your machine?

suppose I could do something like that, I just like datrons way ;)

[JAZZCNC]

is that your machine?

suppose I could do something like that, I just like datrons way ;)

No not my machine and I like Datrons way but I haven't got £5000 + spare so I use £30 toggle clamps/bolts and it takes 1 minute longer.!
I then cut assured that the parts arn't going to slip and slid lossing accurecy or worse still get embedded into my neck when they Vacuum alone decides enoughs enough.!!

Horses for courses really. Vac is great for thin parts with no holes or large parts with few holes. Small with lots or large holes and it quickly becomes not funny.!

Anyway think i've said all that's to be said so hope you make the right choice in end so your wallet is stress free.!! . . . . . .. If not then you really have got too much money. . Lol

[andy_con]

lol

im very grateful for your help

[Boyan Silyavski]

Dean,very illustrative video, that's exactly how i work also. With the addition that when i have pass through profile and holes,sometimes i fix below a 3 mm sacrificial expanded plastic board . The board is not needed when routing wood or plastic, only for aluminum, cause for the aluminum the bit should go a bit in the sacrificial board for a clean cut.

Andy, as for repetitive parts like the panels example, if they come in cut shapes or as i do some hundreds of same pieces, the best solution is to make a custom vacuum fixture. Its not a great deal, simple to make once you know the principles involved and is very useful. Much better than universal table. You once align the fixture and then go.

[GEOFFREY]

Surely for wood the bit needs to fully penetrate the work so therefore a sacrificial (mdf?) board is still required. What type of expanded plastic board do you use as most plastics are virtually impermeable, or do you use some kind of foam board (polystyrene?). G.

[Boyan Silyavski]

Surely for wood the bit needs to fully penetrate the work so therefore a sacrificial (mdf?) board is still required. What type of expanded plastic board do you use as most plastics are virtually impermeable, or do you use some kind of foam board (polystyrene?). G.

3-4mm expanded PVC, used usually as backing for large photo prints. have friends with photo studio and use for free the rests. its sth like 6euro per sq m , sold on sheets of 3x2m. Easily cut wit cutter/exacto knife/. One of my favorite materials.

also from them i get super strong ultra thin double tape sheet, used to stick photo prints to methacrylate. This i use on small pieces for fixing the center not to flap. very strong stuff, if used bigger is impossible to separate. if cutter passes through it though the last cut should be way slower.

If the machine is precise and the table is surfaced plastic or even better- some phenolic sheet, the bit does not need to penetrate more than 0 for wood and plastic.Its very pleasant to the eye how it cuts through and does not damage the surface. of course after auto 0 procedure, preferably using calibrated material touch plate.

Only for aluminum it needs to go deeper as its slightly pushes the last material instead of cuttingwhen set to cut to 0 depth.

[GEOFFREY]

Thanks Boyan. Your machine must be super accurate if you can cut through without marking the undersheet. I have a metal matrix table and neoprene gasket material is fed into the matrix slots to form the vacuum to the the areas where i want to cut. Under vacuum the gasket compresses, more or less flush to the bed, but not 100%. This would certainly preclude only cutting to the spoilboard top, and all the large flatbed routers that I have seen ALWAYS leave a witness mark of some description. G.

[JAZZCNC]

Thanks Boyan. Your machine must be super accurate if you can cut through without marking the undersheet. I have a metal matrix table and neoprene gasket material is fed into the matrix slots to form the vacuum to the the areas where i want to cut. Under vacuum the gasket compresses, more or less flush to the bed, but not 100%. This would certainly preclude only cutting to the spoilboard top, and all the large flatbed routers that I have seen ALWAYS leave a witness mark of some description. G.

This is why you need a thin permeable layer to allow cutting thru without marking base.

Boyan most the Ali plate I cut comes with plastic protection layer and this offers enough cut thru in most cases. I always use finish pass which helps remove most of the burr and then I De-bur anyway so doesn't really cause a problem.

[Boyan Silyavski]

Here is short video of the ebay pump. I went today to my friend and tried it. In Russian, we speak about the additional pieces and that obtaining the clamps from the seller is very important.. Now to have in mind that this is 7cfm pump at the same time only 0.37kw and very quiet. Its 3 phase so as you can see at the video. Definitely worth purchasing if sb is on a hunt for vacuum pump. All extra pieces are custom made.


https://photos.google.com/photo/AF1QipNbHVCOPZ6gsW73p37neQlL-TjnfNiLBkTyDYMU

[andy_con]

wont let me view, says I need an account to view


Here is short video of the ebay pump. I went today to my friend and tried it. In Russian, we speak about the additional pieces and that obtaining the clamps from the seller is very important.. Now to have in mind that this is 7cfm pump at the same time only 0.37kw and very quiet. Its 3 phase so as you can see at the video. Definitely worth purchasing if sb is on a hunt for vacuum pump. All extra pieces are custom made.


https://photos.google.com/photo/AF1QipNbHVCOPZ6gsW73p37neQlL-TjnfNiLBkTyDYMU

[Boyan Silyavski]

Here is the vid in YouTube now.


https://www.youtube.com/watch?v=xLqNP8nCp_E

The connection and bracket are named KF25. plenty of them cheap in ebay.

What you will need more for the system:
-outlet- additional bracket and oil trap filter for the exhaust oil vapors, which is basically a box with sponge inside
-inlet- at least another bracket and hose adapter. Inline air filter at least 5 micron, so no dust enters the sucker. Maybe cheap car fuel filter or sth similar. Liquid separator?
-2 capacitors so you can run it 2 phase. its 3 phase originally. One for start and other to run, see video.

additional notes:
-I don't see a reason for an air reservoir as the system will be very tight and it will take time to achieve pressure with big deposit. Switch on, use and then switch off. This pump has nothing to do with the cheap ones/similar price new/ sold at ebay with similar ratings in CFM, though i believe even they will work ok as here the purpose is not removing the last atom...
-digital vacuum gauge is recommended, though even a analogue will work ok. i don't see actual need for switch except to make some sort of bleed valve when certain vacuum is reached. hopefully there will be some smallish leaks in the diy seal anyway, cause that thing is a sucker.

I am very inclined to grab one. If you are even more patient next week i will go there again, so can try it with some improvised vacuum fixture and make video of it.

[andy_con]

I took the forums advice

http://i187.photobucket.com/albums/x202/magicmushrooms1/cnc/DSC_0800_zpsetbbdrxg.jpg

http://i187.photobucket.com/albums/x202/magicmushrooms1/cnc/DSC_0801_zpstefrq1hn.jpg

http://i187.photobucket.com/albums/x202/magicmushrooms1/cnc/DSC_0803_zpsnplilp1f.jpg

[JAZZCNC]

I took the forums advice

Looking good.!:thumsup:

It's good feeling knowing it's going to stay put and not turn into slitting disc if cutter jams or decide it doesn't like this cutting millarky so turns into flying saucer.!! . .:onthego:

[YulianY]

We develop a thin film for hard works may be it can do the job? Please take a look at the movie. https://www.youtube.com/watch?v=PbCqkUomf5M