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I can't believe that it has been so long since an update. There has been some progress on the Squeeze Box, but has been a slow process. Little things have been coming up at seemingly every stage, pieces not fitting, or not preforming as designed. One of the largest obstacles was the bleeding of the tool. We have in house tools that we use for bleeding the system, and had a plan for users bleeding in the field. While the tool preformed as expected with our system, the in field tools did not. After weeks of head scratching and laying awake at night, I finally decided to go back to a bleed fitting at each end of the hose (getting a bubble out of the middle of the hose was a problem). With Mark's original design of pushing fluid from top to bottom through the system, it requires a bit of fumbling, but it works. The problem with our handle was bleed fitting placement. Finally I decided to put the tool end bleed fitting on the base of the swivel.
I really liked the clean sleek look of our swivel and didn't want to add anything that would catch on items, or add to the length of the tool. However this was the closest place that I could get a standard bleed fitting. I thought of a couple other ideas, but it would have added additional features to existing parts, and necessitated production of custom fittings, and custom bleed tools that would likely add $100+ to the price of the tool. In the end it was decided to go ahead with the design of a new swivel spindle with an integral bleed fitting.
To ensure that the newly designed fitting would work, and equally importantly, would not interfere with the comfort and operation, we had a part 3D printed and installed it on a swivel. There were a few changes based on this plastic part, and we have lathe time scheduled this week to make the aluminum replacements.
Another issue that has come up was with the low pressure side of the intensifier operation. The intensifier has two stages, on that allows the ram to move up to the rivet but will not compress it. The second gives the full pressure to collapse the rivet. These two pressures are set with regulators in the bottom of the box. The high pressure set to 90psi and is simply to prevent someone from plugging into 130psi shop air and blowing up the hydraulic hose. The low pressure is around 8psi and is really hard to measure exactly. What we have been doing is putting in a 426AD3-3 rivet and adjusting to the point where it would not compress it. I think a load cell is the correct long term solution, but any recommendations would be welcome. What we didn't expect... When this is set it will cycle fine, but after the tool sits unused for a time the 8psi is not enough to throw the valve completely open or closed. After some investigation, the electric solenoid is intended to move the position of the piston inside the valve, but it is actually 20psi minimum of air pressure that seals the valve's piston against either end. When sitting for a while it will often leak when not engaged, or simple not engage at all, and sometimes both. The easy solution would be to move the regulator to the other side of the valve, but that messes up the layout of the box (see photos in previous posts). This may be the solution, but I am hoping that another solution will present it'self before the swivel spindles above are finished.
Other problems that we have solved in the last couple months include jigging and fixturing to be able to hold parts while manufacturing, allowing us to get a better idea of final parts cost, figuring out an anodizing problem that lead to powdery looking parts in some batches, and a problem with the circuit board that caused a short when plugging in the foot control and the wall charger at the same time.
Learning all of these new processes in house has been challenging, and rewarding, but has taken MUCH longer than anticipated. One thing about us though is we will not let a product go out the door until we are satisfied that it will preform as we would expect it to if we were the customer. This is important for function, but equally important for finish quality and ergonomics.
I have now committed to weekly updates here in order to keep the interested parties informed.
Thanks to all for patience and interest. - Mike
I really liked the clean sleek look of our swivel and didn't want to add anything that would catch on items, or add to the length of the tool. However this was the closest place that I could get a standard bleed fitting. I thought of a couple other ideas, but it would have added additional features to existing parts, and necessitated production of custom fittings, and custom bleed tools that would likely add $100+ to the price of the tool. In the end it was decided to go ahead with the design of a new swivel spindle with an integral bleed fitting.
Another issue that has come up was with the low pressure side of the intensifier operation. The intensifier has two stages, on that allows the ram to move up to the rivet but will not compress it. The second gives the full pressure to collapse the rivet. These two pressures are set with regulators in the bottom of the box. The high pressure set to 90psi and is simply to prevent someone from plugging into 130psi shop air and blowing up the hydraulic hose. The low pressure is around 8psi and is really hard to measure exactly. What we have been doing is putting in a 426AD3-3 rivet and adjusting to the point where it would not compress it. I think a load cell is the correct long term solution, but any recommendations would be welcome. What we didn't expect... When this is set it will cycle fine, but after the tool sits unused for a time the 8psi is not enough to throw the valve completely open or closed. After some investigation, the electric solenoid is intended to move the position of the piston inside the valve, but it is actually 20psi minimum of air pressure that seals the valve's piston against either end. When sitting for a while it will often leak when not engaged, or simple not engage at all, and sometimes both. The easy solution would be to move the regulator to the other side of the valve, but that messes up the layout of the box (see photos in previous posts). This may be the solution, but I am hoping that another solution will present it'self before the swivel spindles above are finished.
Other problems that we have solved in the last couple months include jigging and fixturing to be able to hold parts while manufacturing, allowing us to get a better idea of final parts cost, figuring out an anodizing problem that lead to powdery looking parts in some batches, and a problem with the circuit board that caused a short when plugging in the foot control and the wall charger at the same time.
Learning all of these new processes in house has been challenging, and rewarding, but has taken MUCH longer than anticipated. One thing about us though is we will not let a product go out the door until we are satisfied that it will preform as we would expect it to if we were the customer. This is important for function, but equally important for finish quality and ergonomics.
I have now committed to weekly updates here in order to keep the interested parties informed.
Thanks to all for patience and interest. - Mike
Mike,
ReplyDeleteWhat I have been doing is not elegant, but seems to work very well: Place tool on floor, intensifier on shop bench, attach full syringe to nipple on intensifier and open bleed fitting. I cycle fluid back and forth, watching the ram extend and come back...after maybe 4-5 of these operations any air in the system will appear in the syringe. I then close the bleed fitting...seems to work well.
Another option I plan on trying (but may be cost prohibitive for a production run) I have a swagelok supplier local. I am thinking of getting a male QD and just attaching it to a reservoir. Connect it to tool end of hose, apply air, cycle intensifier. The flow rate is so small that the flow into and out of the reservoir should be harmless. This will not bleed the tool, but would bleed the intensifier very well.