Cheese
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- Joined
- Jan 16, 2015
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This post is rather lengthy, so if you don't want to read all the details or are a firm advocate of the "One Minute Manager" philosophy, just go down to the conclusion. Let the snoring begin...
This post is in response to a thought I posted about 3 weeks ago. At that time I turned over my newly purchased VAC SYS base and noted the vast vacuum chamber contained underneath. My first thought was that this could potentially be a buffer mechanism if utilized, for a catastrophic vacuum failure. I decided to see if this was indeed the case.
I used a 12” x 12” x ¼” piece of ply to adhere to the vacuum head. The ply was sanded with 180 grit Granat to approximate what the typical usage may entail. The piece of ply is of very light weight and was chosen so that when the vacuum pump was turned off, and when the vacuum had reached a critical level, the spring loaded, green poppet valve, would lift the ply free from the vacuum head and I could then easily record the length of time the ply had been secured to the vacuum head.
So I ran a series of 3 timed tests, and averaged them, not to come to a definitive decay value, but rather to ensure that the short time testing values were indeed indicative of something substantive.
Initial testing was with a Festool clamping module SE 1, connected to a Milwaukee vacuum pump using Festo/Festool vacuum hose, fittings & clamps.
The vacuum was pulled down to 500 mm Hg and allowed to stabilize. The vacuum pump was turned off and the 12” plywood square popped off of the vacuum pad in 9, 10.5 & 11 seconds = 10.2 seconds average.
I then engaged the green slide switch on the SE 1, which evacuates the chamber underneath the vacuum head and pulls the entire SE 1 unit down into contact with a non-porous surface.
The vacuum was again pulled down to 500 mm Hg and allowed to stabilize. The vacuum pump was turned off and the 12” plywood square popped off of the vacuum pad in 113, 112 & 108 seconds = 111 seconds average.
Conclusion:
There is a substantial vacuum reserve available if the vacuum in the SE 1 base is utilized rather than just bolting the SE 1 to a table/bench. It increases the hold time by a factor of 10 [cool] [jawdrop]
Note:
The amount of vacuum that can be generated is dependent upon the surface finish of the component being placed on the vacuum pad. In this situation, the sanded plywood would only allow the pump to pull 500 mm Hg, while using phenolic coated plywood/plastic, the pump can pull over 700 mm Hg.
Along with surface finish, the more vacuum that is pulled, also increases the decay time significantly. I’ve worked with phenolic coated plywood, switched off the pump and 45 minutes later, I could not remove the plywood from the vacuum head because there was still over 450 mm of vacuum in the system.
This post is in response to a thought I posted about 3 weeks ago. At that time I turned over my newly purchased VAC SYS base and noted the vast vacuum chamber contained underneath. My first thought was that this could potentially be a buffer mechanism if utilized, for a catastrophic vacuum failure. I decided to see if this was indeed the case.
I used a 12” x 12” x ¼” piece of ply to adhere to the vacuum head. The ply was sanded with 180 grit Granat to approximate what the typical usage may entail. The piece of ply is of very light weight and was chosen so that when the vacuum pump was turned off, and when the vacuum had reached a critical level, the spring loaded, green poppet valve, would lift the ply free from the vacuum head and I could then easily record the length of time the ply had been secured to the vacuum head.
So I ran a series of 3 timed tests, and averaged them, not to come to a definitive decay value, but rather to ensure that the short time testing values were indeed indicative of something substantive.
Initial testing was with a Festool clamping module SE 1, connected to a Milwaukee vacuum pump using Festo/Festool vacuum hose, fittings & clamps.
The vacuum was pulled down to 500 mm Hg and allowed to stabilize. The vacuum pump was turned off and the 12” plywood square popped off of the vacuum pad in 9, 10.5 & 11 seconds = 10.2 seconds average.
I then engaged the green slide switch on the SE 1, which evacuates the chamber underneath the vacuum head and pulls the entire SE 1 unit down into contact with a non-porous surface.
The vacuum was again pulled down to 500 mm Hg and allowed to stabilize. The vacuum pump was turned off and the 12” plywood square popped off of the vacuum pad in 113, 112 & 108 seconds = 111 seconds average.
Conclusion:
There is a substantial vacuum reserve available if the vacuum in the SE 1 base is utilized rather than just bolting the SE 1 to a table/bench. It increases the hold time by a factor of 10 [cool] [jawdrop]
Note:
The amount of vacuum that can be generated is dependent upon the surface finish of the component being placed on the vacuum pad. In this situation, the sanded plywood would only allow the pump to pull 500 mm Hg, while using phenolic coated plywood/plastic, the pump can pull over 700 mm Hg.
Along with surface finish, the more vacuum that is pulled, also increases the decay time significantly. I’ve worked with phenolic coated plywood, switched off the pump and 45 minutes later, I could not remove the plywood from the vacuum head because there was still over 450 mm of vacuum in the system.
