Easy Automation Improvement Example Vol.9-1
Automatic Sorting System
Changing the speed during movement to reduce the cycle time by 20%
System Overview
This is a reduction gear manufacturing line. The cutting process cuts shaft parts to a specified length, orients them vertically, then transfers them to the next shaft-end machining process.
Air cylinders are used to turn and transfer the shaft materials.
Problems when Air Cylinders are used
Ways to shorten cycle time and boost productivity are being looked at. However, raising the speed increases the stopping impact of the air cylinder and the occurrences of choko-tei, so reducing the cycle time wasn’t feasible.
Shaft parts falling from abrupt stopping impacts are causing the choko-tei.
There are around 15 incidents of choko-tei per day. It takes 3 minutes for the system to recover from each choko-tei incident, meaning that around 45 minutes each day are being wasted.
Improvements Achieved by the ROBO Cylinder®
1. Shorter cycle time and zero choko-tei through speed, acceleration, and deceleration setting functions
By setting the speed and acceleration high and the deceleration gradual, high-speed operation free from stopping shock became possible.
1.5 seconds of travel time was reduced on the Y-axis. Also, the impact-free operation eliminated choko-tei and recovery time.
Relation of Y-axis operating time and speed
Y-axis travel time |
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Air cylinder:
|
ROBO Cylinder:
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Choko-tei recovery time a day(3 minutes/incident) |
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Air cylinder:
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ROBO Cylinder:
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2. Further cycle time reduction by adopting the shortest route
By setting the lowest possible position for the Z-axis cylinder during the return operation, another 0.8 seconds was reduced from the cycle time.
Cycle time |
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Air cylinder:
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ROBO Cylinder:
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3. If the system needs to operate for 10 years, it would require 12 air cylinder replacements. ROBO Cylinder replacements will not be needed.
Air cylinders lose speed (thrust force) after around 2 million operations due to deterioration of the gaskets, etc. The Y-axis and Z-axis air cylinders had to be replaced once every 1.5 years.
ROBO Cylinders can ensure stable operation even after many hours of use. When calculated under the current use conditions, the ROBO Cylinder has a service life of 15 million operations or more. The service life of ROBO Cylinders is equivalent to 10 years or longer.
Number of replacement units |
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Air cylinder:
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ROBO Cylinder:
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Cost Cutting Effect
(1) Conditions
| Required production quantity | 4,800 parts |
| Labor cost | $18*/hour |
| Annual operating days | 250 days |
(2) Comparison of Air Cylinder and ROBO Cylinder®
| Item | System using air cylinder | System using ROBO Cylinder | |
| Modification cost | – | Total cost: $6,700* | |
| Cycle time | 8.7 seconds | 6.4 seconds | |
| Line operating hours | 12.4 hours/day Cycle time 8.7 seconds x 4,800 parts + Choko-tei recovery time 0.75 hours = Approx. 12.4 hours |
8.5 hours/day Cycle time 6.4 seconds x 4,800 parts = Approx. 8.5 hours |
|
| Labor cost | $55,800*/year 12.4 hours/day x $18*/hour x 250 days/year = $55,800* |
$38.250*/year 8.5 hours/day x $18*/hour x 250 days/year = $38,250* |
|
| Purchase cost of replacement cylinders (estimate over 10 years) | $6,900*/year YZ unit air cylinders $1,150* x 6 replacements (replaced regularly once every 1.5 years) = $6,900* |
$0 | |
(3) Cost Cutting Effect
| Air cylinder | ROBO Cylinder | ||
| Labor Cost (annual) | $55,800* – | $38,250* = | $17,550* |
| Difference = | $17,550* | ||
| Purchase cost of replacement cylinders (annual) | $690* – (Air cylinder $6,900*/10years) |
$0 = | $690* |
| Difference = | $690* |
Result
By adopting the ROBO Cylinder, it reduced cycle time by 34%,
eliminated choko-tei, and achieved $17,550* in annual savings.
Also, the ROBO Cylinder doesn’t need replacing for at least 10 years.
It will help save another $690* in air cylinder replacement costs every year.
* Exchange Rate: 1(USD) = 100(Japanese Yen)