Re: [Emc-users] OT: About a chat here on vacuum table ideas
Hello all and thanks again for all the feedback, Well, to clarify a little bit more this is what I have and I what I intend to do: I'm planning to use the router to cut just sheets of MDF and Melamine with compression toolbits mostly, and some drilling too, all carbide off course. I do have a 3 hp side blower that was used to suck wood chips from another machine. My idea was to start with that pump to see if it can handle the task. I can't try all this already because the router is almost finished but not yet. But since it's almost the end of the project I think this is the moment to start worrying about the bed subject. So basically, I will have to try the MDF spoil board without holes to see if that works and if not, just try another material not so permeable with the pellets and springs. I have several weeks yet to decide what to do. Best wishes to all! El jue, 10 jun 2021 a las 10:28, Les Newell () escribió: > That's very good info. If you are doing mass production and starting > with blanks or pre-machined parts then pods are the way to go, no doubt. > However if you are machining parts out of sheet then you want vacuum on > the whole table. Table vacuum is generally more versatile but usually > needs some creativity when it comes to holding smaller parts. > > I see a few suggestions to skim your spoil board to improve flow. In my > personal opinion that is not always a good thing. The higher the > permeability of the board the more flow you get in exposed areas. Flow > rate and pressure drop are directly related. If you decrease the flow > rate the pressure drop across the board decreases. > Take two areas of the board, one is covered with an impermeable object > and the other is open. The open area has no limit to the available air > so the pressure drop across the board is high and the flow rate is high. > However in the case of the covered area, little or no air flows through > the covering so there is very little pressure drop across the board. > Your part sees nearly the full vacuum. > If you are cutting impermeable materials such as plastics or alubond > you want a very restrictive spoil board to reduce lost vacuum in the cut > areas. If you are cutting permeable materials such as MDF you need less > restriction in the spoil board to compensate for the flow through your > work. It's a complicated subject and the only real solution is to > experiment and see what works for your setup. > > Les > > On 09/06/2021 21:00, Todd Zuercher wrote: > > There is a wide discrepancy between the levels of vacuum that different > types of vacuum pumps and blowers can generate. Some kinds are rotary > screw pumps, liquid ring pumps, rotary vane pumps, positive displacement > blowers like a roots blower, or regenerative blowers (which are more like a > fan). You need to consider both the level of vacuum you need to attain and > the amount of air you need to move to get there. Compare a 10HP regen > blower, vs a 10HP rotary vane pump. The regen blower can move 4 times as > much air as the positive displacement vane pump. But the vain pump can > draw more than twice the vacuum level. Which would hold a part better will > depend a lot on table design and area. An open hole table with small > pockets over the holes can work very well with the blower, but the blower > will struggle trying to hold small parts on a fall board. The vane pump > would work great on closed pods and jigs or a smaller fall board, but if > the table is very large or an open flow design it won't be able to keep up > and vacuum levels could fall too low. > > > > A 5ft x 10ft fall board (sheet of MDF that has been skinned can flow > nearly 300acfm (maybe a bit more) of air when a 15inHg vaccum is applied to > it. But if you need 20inHg to hold your parts, you're going to need a much > larger and more powerful pump to get there (probably at least double). But > if you only need 10inHG the flow through the board will be much less > probably closer to 100ACFM. The greater the pressure differential the > higher the flow and leakage. This is why gasketed jigs and pods work so > much better for holding pieces. You don't have the flow to contend with, > you only need a pump capable of generating the pressure level you need and > the ACFMs of the pump are less important. > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
That's very good info. If you are doing mass production and starting with blanks or pre-machined parts then pods are the way to go, no doubt. However if you are machining parts out of sheet then you want vacuum on the whole table. Table vacuum is generally more versatile but usually needs some creativity when it comes to holding smaller parts. I see a few suggestions to skim your spoil board to improve flow. In my personal opinion that is not always a good thing. The higher the permeability of the board the more flow you get in exposed areas. Flow rate and pressure drop are directly related. If you decrease the flow rate the pressure drop across the board decreases. Take two areas of the board, one is covered with an impermeable object and the other is open. The open area has no limit to the available air so the pressure drop across the board is high and the flow rate is high. However in the case of the covered area, little or no air flows through the covering so there is very little pressure drop across the board. Your part sees nearly the full vacuum. If you are cutting impermeable materials such as plastics or alubond you want a very restrictive spoil board to reduce lost vacuum in the cut areas. If you are cutting permeable materials such as MDF you need less restriction in the spoil board to compensate for the flow through your work. It's a complicated subject and the only real solution is to experiment and see what works for your setup. Les On 09/06/2021 21:00, Todd Zuercher wrote: There is a wide discrepancy between the levels of vacuum that different types of vacuum pumps and blowers can generate. Some kinds are rotary screw pumps, liquid ring pumps, rotary vane pumps, positive displacement blowers like a roots blower, or regenerative blowers (which are more like a fan). You need to consider both the level of vacuum you need to attain and the amount of air you need to move to get there. Compare a 10HP regen blower, vs a 10HP rotary vane pump. The regen blower can move 4 times as much air as the positive displacement vane pump. But the vain pump can draw more than twice the vacuum level. Which would hold a part better will depend a lot on table design and area. An open hole table with small pockets over the holes can work very well with the blower, but the blower will struggle trying to hold small parts on a fall board. The vane pump would work great on closed pods and jigs or a smaller fall board, but if the table is very large or an open flow design it won't be able to keep up and vacuum levels could fall too low. A 5ft x 10ft fall board (sheet of MDF that has been skinned can flow nearly 300acfm (maybe a bit more) of air when a 15inHg vaccum is applied to it. But if you need 20inHg to hold your parts, you're going to need a much larger and more powerful pump to get there (probably at least double). But if you only need 10inHG the flow through the board will be much less probably closer to 100ACFM. The greater the pressure differential the higher the flow and leakage. This is why gasketed jigs and pods work so much better for holding pieces. You don't have the flow to contend with, you only need a pump capable of generating the pressure level you need and the ACFMs of the pump are less important. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
There is a wide discrepancy between the levels of vacuum that different types of vacuum pumps and blowers can generate. Some kinds are rotary screw pumps, liquid ring pumps, rotary vane pumps, positive displacement blowers like a roots blower, or regenerative blowers (which are more like a fan). You need to consider both the level of vacuum you need to attain and the amount of air you need to move to get there. Compare a 10HP regen blower, vs a 10HP rotary vane pump. The regen blower can move 4 times as much air as the positive displacement vane pump. But the vain pump can draw more than twice the vacuum level. Which would hold a part better will depend a lot on table design and area. An open hole table with small pockets over the holes can work very well with the blower, but the blower will struggle trying to hold small parts on a fall board. The vane pump would work great on closed pods and jigs or a smaller fall board, but if the table is very large or an open flow design it won't be able to keep up and vacuum levels could fall too low. A 5ft x 10ft fall board (sheet of MDF that has been skinned can flow nearly 300acfm (maybe a bit more) of air when a 15inHg vaccum is applied to it. But if you need 20inHg to hold your parts, you're going to need a much larger and more powerful pump to get there (probably at least double). But if you only need 10inHG the flow through the board will be much less probably closer to 100ACFM. The greater the pressure differential the higher the flow and leakage. This is why gasketed jigs and pods work so much better for holding pieces. You don't have the flow to contend with, you only need a pump capable of generating the pressure level you need and the ACFMs of the pump are less important. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -Original Message- From: Les Newell Sent: Wednesday, June 09, 2021 2:42 PM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas [EXTERNAL EMAIL] Be sure links are safe. I tested a 1.5kW vacuum cleaner motor for this application a while back and wasn't impressed. They don't generate enough vacuum in my opinion. You really need vane pumps or side channel blowers. Vane pumps generate a very strong vacuum but use a lot of power. Side channel blowers generate more flow for the same power but less vacuum. I used to operate a machine with a 1.2m x 2.4 bed that had two 2kW side channel blowers and the vacuum was marginal. I did have parts move occasionally. Les On 09/06/2021 16:31, Roland Jollivet wrote: > A friend was complaining about the need for 6kW vacuum system on a > large table and this got me thinking > > Another way is to divide the table up into squares, grid wise, and > have a .. separate.. vacuum motor for each section. The motor is > mounted under the table at the bottom of each 'box'. > You can get ~1.5kW motors really cheap, and now it's easy to make up a > system with as many kW as you want. > > Far easier to find 4 vacuum motors than a 6kW pump. > > Roland > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
I tested a 1.5kW vacuum cleaner motor for this application a while back and wasn't impressed. They don't generate enough vacuum in my opinion. You really need vane pumps or side channel blowers. Vane pumps generate a very strong vacuum but use a lot of power. Side channel blowers generate more flow for the same power but less vacuum. I used to operate a machine with a 1.2m x 2.4 bed that had two 2kW side channel blowers and the vacuum was marginal. I did have parts move occasionally. Les On 09/06/2021 16:31, Roland Jollivet wrote: A friend was complaining about the need for 6kW vacuum system on a large table and this got me thinking Another way is to divide the table up into squares, grid wise, and have a .. separate.. vacuum motor for each section. The motor is mounted under the table at the bottom of each 'box'. You can get ~1.5kW motors really cheap, and now it's easy to make up a system with as many kW as you want. Far easier to find 4 vacuum motors than a 6kW pump. Roland ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
Some CNC lasers and plasma cutters use zoned smoke collection system that opens different shutters depending on the gantry position. Might something similar work for holding the workpiece? Thaddeus Waldner Newdale School Elkton, SD 57026 From: Roland Jollivet Sent: Wednesday, June 9, 2021 10:31:01 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas A friend was complaining about the need for 6kW vacuum system on a large table and this got me thinking Another way is to divide the table up into squares, grid wise, and have a .. separate.. vacuum motor for each section. The motor is mounted under the table at the bottom of each 'box'. You can get ~1.5kW motors really cheap, and now it's easy to make up a system with as many kW as you want. Far easier to find 4 vacuum motors than a 6kW pump. Roland On Wed, 9 Jun 2021 at 17:13, Todd Zuercher wrote: > For milling sheet material on a large table, an MDF spoil board on top of > a vacuum grid is usually the best option. But for small parts such as > solid wood items vacuum pods are usually a better choice. In a pod > arrangement with the part held directly is where the valves are useful. > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -Original Message- > From: Leonardo Marsaglia > Sent: Tuesday, June 08, 2021 10:47 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas > > [EXTERNAL EMAIL] Be sure links are safe. > > Thank you guys for your answers! > > I've been reading and apparently MDF with a skim cut is pretty good to > distribute the vacuum all around it's surface given its porosity. I think > I'm gonna try that option first to see how severe is the vacuum loss when > the cuts are made. > > Second option would be what Todd suggests, wich is a little trickier > mostly because my surface needs to be 3000 mm x 2000 mm, so that's a lot of > springs... > > I'll keep you informed as the project progresses. > > Thanks as always for your help :) > > El lun, 7 jun 2021 a las 17:11, Todd Zuercher () > escribió: > > > It might work, but you may have trouble with the pellet sticking in > > the seat and not opening when you need it to, or worse yet if your > > part doen't quite seal good enough to the table, sucking shut and > > losing all holding power. > > > > What I've seen more commonly used is a spring loaded valve where a > > spring pushes the pellet(ball) up to seal the vacuum port. When no > > part is in place the spring pushes the ball up to seal the vacuum > > port, and the ball sticks up a bit above the part sealing surface. > > When the part is placed on top, it pushes the ball down opening the > > valve and allowing the vacuum to flow. > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -Original Message- > > From: Leonardo Marsaglia > > Sent: Saturday, June 05, 2021 11:50 PM > > To: Enhanced Machine Controller (EMC) > > > > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > I meant to say: > > > > When there is a part over that hole and before the pump is on, the > > pellet will be resting on the groove. As soon as the pump is on the > > vacuum will be immediately sealed by the part, not allowing the > > suction to suck the pellet > > > > El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia > > ( > >) > > escribió: > > > > > Hello guys, > > > > > > I hope you're all doing well. > > > > > > Not so long ago (or may be yes) I recall reading someone on this > > > list talking about an idea of using plastic pellets as closing > > > valves for an MDF vacuum table. > > > > > > The basic idea was: The pellet falls into a spherical hole that has > > > a round groove with a slight angle on its side. So when the vacuum > > > is not applied the plastic pellet can slide thru the groove and > > > leave the hole open (I imagine that the vacuum pump could be > > > reversed so one can blow to clear the holes and force the pellets to > the groove quicker). > > > When there is a part over that hole and before the pump is on, the > > > vacuum will be immediately sealed by the part, not allowing the > > > suction to suck the pellet. Once the hole is again free
Re: [Emc-users] OT: About a chat here on vacuum table ideas
A friend was complaining about the need for 6kW vacuum system on a large table and this got me thinking Another way is to divide the table up into squares, grid wise, and have a .. separate.. vacuum motor for each section. The motor is mounted under the table at the bottom of each 'box'. You can get ~1.5kW motors really cheap, and now it's easy to make up a system with as many kW as you want. Far easier to find 4 vacuum motors than a 6kW pump. Roland On Wed, 9 Jun 2021 at 17:13, Todd Zuercher wrote: > For milling sheet material on a large table, an MDF spoil board on top of > a vacuum grid is usually the best option. But for small parts such as > solid wood items vacuum pods are usually a better choice. In a pod > arrangement with the part held directly is where the valves are useful. > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -Original Message- > From: Leonardo Marsaglia > Sent: Tuesday, June 08, 2021 10:47 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas > > [EXTERNAL EMAIL] Be sure links are safe. > > Thank you guys for your answers! > > I've been reading and apparently MDF with a skim cut is pretty good to > distribute the vacuum all around it's surface given its porosity. I think > I'm gonna try that option first to see how severe is the vacuum loss when > the cuts are made. > > Second option would be what Todd suggests, wich is a little trickier > mostly because my surface needs to be 3000 mm x 2000 mm, so that's a lot of > springs... > > I'll keep you informed as the project progresses. > > Thanks as always for your help :) > > El lun, 7 jun 2021 a las 17:11, Todd Zuercher () > escribió: > > > It might work, but you may have trouble with the pellet sticking in > > the seat and not opening when you need it to, or worse yet if your > > part doen't quite seal good enough to the table, sucking shut and > > losing all holding power. > > > > What I've seen more commonly used is a spring loaded valve where a > > spring pushes the pellet(ball) up to seal the vacuum port. When no > > part is in place the spring pushes the ball up to seal the vacuum > > port, and the ball sticks up a bit above the part sealing surface. > > When the part is placed on top, it pushes the ball down opening the > > valve and allowing the vacuum to flow. > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -Original Message- > > From: Leonardo Marsaglia > > Sent: Saturday, June 05, 2021 11:50 PM > > To: Enhanced Machine Controller (EMC) > > > > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > I meant to say: > > > > When there is a part over that hole and before the pump is on, the > > pellet will be resting on the groove. As soon as the pump is on the > > vacuum will be immediately sealed by the part, not allowing the > > suction to suck the pellet > > > > El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia > > ( > >) > > escribió: > > > > > Hello guys, > > > > > > I hope you're all doing well. > > > > > > Not so long ago (or may be yes) I recall reading someone on this > > > list talking about an idea of using plastic pellets as closing > > > valves for an MDF vacuum table. > > > > > > The basic idea was: The pellet falls into a spherical hole that has > > > a round groove with a slight angle on its side. So when the vacuum > > > is not applied the plastic pellet can slide thru the groove and > > > leave the hole open (I imagine that the vacuum pump could be > > > reversed so one can blow to clear the holes and force the pellets to > the groove quicker). > > > When there is a part over that hole and before the pump is on, the > > > vacuum will be immediately sealed by the part, not allowing the > > > suction to suck the pellet. Once the hole is again free, the suction > > > will slide the pellet until the hole is sealed (useful to avoid > > > vacuum loses on the path where the tool cuts the material). > > > > > > Are there any practical examples or any real life experience of this > > idea? > > > That would be more than useful. > > > > > > Thanks as always! > > > > > > > ___ > >
Re: [Emc-users] OT: About a chat here on vacuum table ideas
For milling sheet material on a large table, an MDF spoil board on top of a vacuum grid is usually the best option. But for small parts such as solid wood items vacuum pods are usually a better choice. In a pod arrangement with the part held directly is where the valves are useful. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -Original Message- From: Leonardo Marsaglia Sent: Tuesday, June 08, 2021 10:47 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas [EXTERNAL EMAIL] Be sure links are safe. Thank you guys for your answers! I've been reading and apparently MDF with a skim cut is pretty good to distribute the vacuum all around it's surface given its porosity. I think I'm gonna try that option first to see how severe is the vacuum loss when the cuts are made. Second option would be what Todd suggests, wich is a little trickier mostly because my surface needs to be 3000 mm x 2000 mm, so that's a lot of springs... I'll keep you informed as the project progresses. Thanks as always for your help :) El lun, 7 jun 2021 a las 17:11, Todd Zuercher () escribió: > It might work, but you may have trouble with the pellet sticking in > the seat and not opening when you need it to, or worse yet if your > part doen't quite seal good enough to the table, sucking shut and > losing all holding power. > > What I've seen more commonly used is a spring loaded valve where a > spring pushes the pellet(ball) up to seal the vacuum port. When no > part is in place the spring pushes the ball up to seal the vacuum > port, and the ball sticks up a bit above the part sealing surface. > When the part is placed on top, it pushes the ball down opening the > valve and allowing the vacuum to flow. > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -Original Message- > From: Leonardo Marsaglia > Sent: Saturday, June 05, 2021 11:50 PM > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas > > [EXTERNAL EMAIL] Be sure links are safe. > > I meant to say: > > When there is a part over that hole and before the pump is on, the > pellet will be resting on the groove. As soon as the pump is on the > vacuum will be immediately sealed by the part, not allowing the > suction to suck the pellet > > El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia > ( >) > escribió: > > > Hello guys, > > > > I hope you're all doing well. > > > > Not so long ago (or may be yes) I recall reading someone on this > > list talking about an idea of using plastic pellets as closing > > valves for an MDF vacuum table. > > > > The basic idea was: The pellet falls into a spherical hole that has > > a round groove with a slight angle on its side. So when the vacuum > > is not applied the plastic pellet can slide thru the groove and > > leave the hole open (I imagine that the vacuum pump could be > > reversed so one can blow to clear the holes and force the pellets to the > > groove quicker). > > When there is a part over that hole and before the pump is on, the > > vacuum will be immediately sealed by the part, not allowing the > > suction to suck the pellet. Once the hole is again free, the suction > > will slide the pellet until the hole is sealed (useful to avoid > > vacuum loses on the path where the tool cuts the material). > > > > Are there any practical examples or any real life experience of this > idea? > > That would be more than useful. > > > > Thanks as always! > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
On Tue, Jun 8, 2021 at 10:49 PM Leonardo Marsaglia wrote: > I've been reading and apparently MDF with a skim cut is pretty good to > distribute the vacuum all around it's surface given its porosity. I think > I'm gonna try that option first to see how severe is the vacuum loss when > the cuts are made. We cover the exposed parts of our spoilboard with plastic sheet or aluminum foil or whatever, to avoid losing vacuum. But we are only doing drag-knife cutting on it, not milling. We don't have a strong enough vacuum pump to do milling. The one time we tried, the part shifted. YouTube has lots of videos of vacuum routers and you can see everything when they show how to replace the spoilboard etc. Cheers ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
1/4" MDF is too thin to skin off the dense layers. (It almost doesn't' even have a porous core like thicker MDFs) And it doesn't offer much protection from coding mistakes. I prefer 3/4" MDF and then mill off about 0.05" off of each sided to open it up. Then you have enough thickness to skim off layers as needed to get a good smooth holding surface after running a few different files. We typically remove only 0.01" when resurfacing the spoilboard. Then replace the spoil board when it gets to be less than about 0.35" thick. We run 3 shifts a day and a new spoilboard will typically last us about a month on a machine. As to vacuum requirements for a 5ftx10ft table and spoil board I like to have about 300ACFM (200 minimum) and be able to maintain at least 15inHg, which typically takes at least about a 10hp vacuum pump (20hp would be much better.) Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -Original Message- From: Les Newell Sent: Wednesday, June 09, 2021 9:25 AM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas [EXTERNAL EMAIL] Be sure links are safe. Yes, 6mm (1/4") MDF works well. It has a bit of restriction so you don't lose all of your vacuum when you cut right through your parts. What sort of vacuum pumps did you have in mind? You'll probably need a minimum of 250 cubic metres per hour for decent hold down. In terms of motor size, that's getting on towards 7.5kw /10HP. Les On 09/06/2021 03:46, Leonardo Marsaglia wrote: > Thank you guys for your answers! > > I've been reading and apparently MDF with a skim cut is pretty good to > distribute the vacuum all around it's surface given its porosity. I > think I'm gonna try that option first to see how severe is the vacuum > loss when the cuts are made. > > Second option would be what Todd suggests, wich is a little trickier > mostly because my surface needs to be 3000 mm x 2000 mm, so that's a > lot of springs... > > I'll keep you informed as the project progresses. > > Thanks as always for your help :) ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
Yes, 6mm (1/4") MDF works well. It has a bit of restriction so you don't lose all of your vacuum when you cut right through your parts. What sort of vacuum pumps did you have in mind? You'll probably need a minimum of 250 cubic metres per hour for decent hold down. In terms of motor size, that's getting on towards 7.5kw /10HP. Les On 09/06/2021 03:46, Leonardo Marsaglia wrote: Thank you guys for your answers! I've been reading and apparently MDF with a skim cut is pretty good to distribute the vacuum all around it's surface given its porosity. I think I'm gonna try that option first to see how severe is the vacuum loss when the cuts are made. Second option would be what Todd suggests, wich is a little trickier mostly because my surface needs to be 3000 mm x 2000 mm, so that's a lot of springs... I'll keep you informed as the project progresses. Thanks as always for your help :) ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
Thank you guys for your answers! I've been reading and apparently MDF with a skim cut is pretty good to distribute the vacuum all around it's surface given its porosity. I think I'm gonna try that option first to see how severe is the vacuum loss when the cuts are made. Second option would be what Todd suggests, wich is a little trickier mostly because my surface needs to be 3000 mm x 2000 mm, so that's a lot of springs... I'll keep you informed as the project progresses. Thanks as always for your help :) El lun, 7 jun 2021 a las 17:11, Todd Zuercher () escribió: > It might work, but you may have trouble with the pellet sticking in the > seat and not opening when you need it to, or worse yet if your part doen't > quite seal good enough to the table, sucking shut and losing all holding > power. > > What I've seen more commonly used is a spring loaded valve where a spring > pushes the pellet(ball) up to seal the vacuum port. When no part is in > place the spring pushes the ball up to seal the vacuum port, and the ball > sticks up a bit above the part sealing surface. When the part is placed on > top, it pushes the ball down opening the valve and allowing the vacuum to > flow. > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -Original Message- > From: Leonardo Marsaglia > Sent: Saturday, June 05, 2021 11:50 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas > > [EXTERNAL EMAIL] Be sure links are safe. > > I meant to say: > > When there is a part over that hole and before the pump is on, the pellet > will be resting on the groove. As soon as the pump is on the vacuum will be > immediately sealed by the part, not allowing the suction to suck the pellet > > El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia ( >) > escribió: > > > Hello guys, > > > > I hope you're all doing well. > > > > Not so long ago (or may be yes) I recall reading someone on this list > > talking about an idea of using plastic pellets as closing valves for > > an MDF vacuum table. > > > > The basic idea was: The pellet falls into a spherical hole that has a > > round groove with a slight angle on its side. So when the vacuum is > > not applied the plastic pellet can slide thru the groove and leave the > > hole open (I imagine that the vacuum pump could be reversed so one can > > blow to clear the holes and force the pellets to the groove quicker). > > When there is a part over that hole and before the pump is on, the > > vacuum will be immediately sealed by the part, not allowing the > > suction to suck the pellet. Once the hole is again free, the suction > > will slide the pellet until the hole is sealed (useful to avoid vacuum > > loses on the path where the tool cuts the material). > > > > Are there any practical examples or any real life experience of this > idea? > > That would be more than useful. > > > > Thanks as always! > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
It might work, but you may have trouble with the pellet sticking in the seat and not opening when you need it to, or worse yet if your part doen't quite seal good enough to the table, sucking shut and losing all holding power. What I've seen more commonly used is a spring loaded valve where a spring pushes the pellet(ball) up to seal the vacuum port. When no part is in place the spring pushes the ball up to seal the vacuum port, and the ball sticks up a bit above the part sealing surface. When the part is placed on top, it pushes the ball down opening the valve and allowing the vacuum to flow. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -Original Message- From: Leonardo Marsaglia Sent: Saturday, June 05, 2021 11:50 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas [EXTERNAL EMAIL] Be sure links are safe. I meant to say: When there is a part over that hole and before the pump is on, the pellet will be resting on the groove. As soon as the pump is on the vacuum will be immediately sealed by the part, not allowing the suction to suck the pellet El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia () escribió: > Hello guys, > > I hope you're all doing well. > > Not so long ago (or may be yes) I recall reading someone on this list > talking about an idea of using plastic pellets as closing valves for > an MDF vacuum table. > > The basic idea was: The pellet falls into a spherical hole that has a > round groove with a slight angle on its side. So when the vacuum is > not applied the plastic pellet can slide thru the groove and leave the > hole open (I imagine that the vacuum pump could be reversed so one can > blow to clear the holes and force the pellets to the groove quicker). > When there is a part over that hole and before the pump is on, the > vacuum will be immediately sealed by the part, not allowing the > suction to suck the pellet. Once the hole is again free, the suction > will slide the pellet until the hole is sealed (useful to avoid vacuum > loses on the path where the tool cuts the material). > > Are there any practical examples or any real life experience of this idea? > That would be more than useful. > > Thanks as always! > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] OT: About a chat here on vacuum table ideas
I meant to say: When there is a part over that hole and before the pump is on, the pellet will be resting on the groove. As soon as the pump is on the vacuum will be immediately sealed by the part, not allowing the suction to suck the pellet El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia () escribió: > Hello guys, > > I hope you're all doing well. > > Not so long ago (or may be yes) I recall reading someone on this list > talking about an idea of using plastic pellets as closing valves for an MDF > vacuum table. > > The basic idea was: The pellet falls into a spherical hole that has a > round groove with a slight angle on its side. So when the vacuum is not > applied the plastic pellet can slide thru the groove and leave the hole > open (I imagine that the vacuum pump could be reversed so one can blow to > clear the holes and force the pellets to the groove quicker). When there is > a part over that hole and before the pump is on, the vacuum will be > immediately sealed by the part, not allowing the suction to suck the > pellet. Once the hole is again free, the suction will slide the pellet > until the hole is sealed (useful to avoid vacuum loses on the path where > the tool cuts the material). > > Are there any practical examples or any real life experience of this idea? > That would be more than useful. > > Thanks as always! > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
