Vacuum
Vacuum Testing
June 20, 2010 09:43 PM
With my shiny new camera in hand I have been snapping pictures and video like there’s no tomorrow. Vacuum parts arrived Thursday and I spent the day cataloging and familiarizing myself with the new stuff. Overall the vacuum generator is absolutely satisfactory. I have found a few clever usage scenarios for it including the planned vacuum cup attachment as well as possible application in variable pressure links.
First are photos of the components I received:
The Venturi Vacuum Generator with fittings
The Clippard Proportional Valve: This item is much smaller than I anticipated and its airflow is lower than I was expecting. Its usefulness might be limited.
Two of the three types of vacuum cups. VC-356 (left) is made of soft, thin silicone. VC-359 (right) is made of a sturdier, but still flexible vinyl. Each have a lip diameter of about 1”.
The third type of vacuum cup: VC-B3. Each of these is made of vinyl and are about .6” in diameter.
I made a video that qualitatively demonstrates the differences between each vacuum cup when attached to a spoon.
In addition to testing with the spoon I did some minimum pressure tests to quantitively differentiate between the three cups I have on hand. In my test I lifted a 568g (1.25lbs) rubber hunk with each cup, and slowly reduced the input pressure to the venturi until the hunk fell from lack of suction. The results of the test are as follows:
What I can say after looking at these numbers in addition to the qualitative testing is that the VC-359 has by far the best lifting potential granted it is able to get an initial grasp. The VC-356 cup is very soft, and despite being the same size as the VC-359 has significantly worse lifting and holding potential. The small VC-B3 lacks the flexibility of the VC-359 cup (one convolution vs. two) so is more subject to disengaging when a moment is applied to the cup. It also has worse lifting/holding performance than the VC-359 due to its smaller diameter.
My next step is to put multiple VC-B3 cups together and test their combined performance. My thought is that there is an optimal arrangement of the three cups such that they have a more desirable grasp on any of the task objects: Spoon, Fork, Toothbrush and Cup.
First are photos of the components I received:
The Venturi Vacuum Generator with fittings
The Clippard Proportional Valve: This item is much smaller than I anticipated and its airflow is lower than I was expecting. Its usefulness might be limited.
Two of the three types of vacuum cups. VC-356 (left) is made of soft, thin silicone. VC-359 (right) is made of a sturdier, but still flexible vinyl. Each have a lip diameter of about 1”.
The third type of vacuum cup: VC-B3. Each of these is made of vinyl and are about .6” in diameter.
I made a video that qualitatively demonstrates the differences between each vacuum cup when attached to a spoon.
In addition to testing with the spoon I did some minimum pressure tests to quantitively differentiate between the three cups I have on hand. In my test I lifted a 568g (1.25lbs) rubber hunk with each cup, and slowly reduced the input pressure to the venturi until the hunk fell from lack of suction. The results of the test are as follows:
| Cup | Fail Input psi |
| VC-356 | 50 psi |
| VC-359 | 15 psi |
| VC-B3 | 41 psi |
What I can say after looking at these numbers in addition to the qualitative testing is that the VC-359 has by far the best lifting potential granted it is able to get an initial grasp. The VC-356 cup is very soft, and despite being the same size as the VC-359 has significantly worse lifting and holding potential. The small VC-B3 lacks the flexibility of the VC-359 cup (one convolution vs. two) so is more subject to disengaging when a moment is applied to the cup. It also has worse lifting/holding performance than the VC-359 due to its smaller diameter.
My next step is to put multiple VC-B3 cups together and test their combined performance. My thought is that there is an optimal arrangement of the three cups such that they have a more desirable grasp on any of the task objects: Spoon, Fork, Toothbrush and Cup.
Comments
System Review
June 11, 2010 09:17 PM
Thursday consisted of finalizing the parts order for the vacuum cups. Friday was a review of the systems at Lab Meeting and a start on inflatables.
The invoice from Keystone Components follows:
Keystone6_10_10
The majority of the components on this list are from Clippard Minimatic. The Vacuum Transducer (Venturi Generator) was sourced from Air-Vac. The vacuum cups are all from Vi-Cas. Each cup is outfitted with a unified fitting to easily connect to the rest of the system. There are three different cup sizes in the order: two with lip diameters near 1” and lifting capacities near 4 pounds, and one with a lip diameter of .6”, capable of lifting much less. This smaller cup was purchased with two like cups to be used in tandem for interesting lifting arrangements. If the vacuum cup solution seems promising I will consider purchasing a dedicated vacuum pump (or compressor, depending on my satisfaction with the Venturi generator) and perhaps other vacuum cups in order to try more gripping setups.
I made the Keystone Components order with a salesman named Mike Albright. He was extremely helpful in organizing the order, was patient with my indecision and inexperience and we were able to work out what seems to be a strong system. I plan to request him specifically when next dealing with Keystone.
Friday included the usual lab meeting where I presented my system overview including a detailed explanation of the vacuum components. I got some valuable feedback that suggested a simple route that did not include using either the existing inflatable arm or continuum arm to accomplish the task I set out. The proposed baseline and a more advanced concept are detailed below:
Chris’ Depiction of Summer Goals.
This drawing followed my presentation, which can be found here:
6_11_10 Lab Meeting
In other news, I was able to solve the puzzle cube bestowed upon me by Sid. My summer work is finished.
The solved cube in all its glory.
The invoice from Keystone Components follows:
Keystone6_10_10
The majority of the components on this list are from Clippard Minimatic. The Vacuum Transducer (Venturi Generator) was sourced from Air-Vac. The vacuum cups are all from Vi-Cas. Each cup is outfitted with a unified fitting to easily connect to the rest of the system. There are three different cup sizes in the order: two with lip diameters near 1” and lifting capacities near 4 pounds, and one with a lip diameter of .6”, capable of lifting much less. This smaller cup was purchased with two like cups to be used in tandem for interesting lifting arrangements. If the vacuum cup solution seems promising I will consider purchasing a dedicated vacuum pump (or compressor, depending on my satisfaction with the Venturi generator) and perhaps other vacuum cups in order to try more gripping setups.
I made the Keystone Components order with a salesman named Mike Albright. He was extremely helpful in organizing the order, was patient with my indecision and inexperience and we were able to work out what seems to be a strong system. I plan to request him specifically when next dealing with Keystone.
Friday included the usual lab meeting where I presented my system overview including a detailed explanation of the vacuum components. I got some valuable feedback that suggested a simple route that did not include using either the existing inflatable arm or continuum arm to accomplish the task I set out. The proposed baseline and a more advanced concept are detailed below:
Chris’ Depiction of Summer Goals.
This drawing followed my presentation, which can be found here:
6_11_10 Lab Meeting
In other news, I was able to solve the puzzle cube bestowed upon me by Sid. My summer work is finished.
The solved cube in all its glory.