(kssc)We are a global supplier of tools, plant industry and power plant, car manufacturing machinery and maintenance equipment to meet the needs of our customers.

Case Studies

Case1.SAMPLE FOR IMPROVED VACUUM DEVICE FOR PRESS MACHINE STEEL

【DEFECT】UNIT DAMAGE BY

SELF NEGATIVE PRESSURE OF VACUUM CUP(DETECTING UP-END OF VACUUM CUP CYLINDER, ABNORMAL STOP)

【RESULT】 Vacuum clamp error occurred and line stopped about once a month. (Replacement work is difficult.)

CYLINDER RETURN-END
CYLINDER RETURN-END
【MAKER'S COMMENT】 Same machines are used in Japan, but no problems have reported so far.
It is not possible for the structure to cause big force enough to deform stopper.

【IDENTIFICATION OF CAUSE】

The deficit product was returned to maker, and measured shaft to identify the cause.

【RESULT OF MEASUREMENT BY MAKER】

1. RESULT OF MEASUREMENT

After measuring the returned part, we found process accuracy didn't reach what it should be.
Size which stopper covers ring should be 0.195mm as shown in pink color on the below drawing, but the size of returned item is shorter, 0.0885mm.

Damaged part is shorter than that; close to zero. So it is supposed stopper overran ring.

2. Solution

To solve the problem caused by bad process accuracy, we will change the shaft to integrated structure.
(Disuse of custom-made stopper and general purchase ring)


End user didn't accept maker's solution, and submitted additional request.

【End User's Additional Requests】

1. As stopper was disformated at the previous trouble, please improve stopper strength.

2. As o-ring tends to to be damaged due to foreign matters, please change lower o-ring (cup side) to dust seal.

***Maker's Engineering Dept. comment the above requests are difficult, and they are under consideration how they can respond them.

  • Space is not enough for dust seal. Drastic modification will be required.
  • Dust seal possibly cannot keep enough air-tightness.
End User's Additional Requests

【Re-Investigation of Cause】

As maker didn't reach clear conclusion after measurement and discussion, they decided to re-investigate at site.

【Re-Investigation Result】
  • They disassembled vacuum pad to see the current conditions at site.

(1)Shaft
Shaft

(2)Guide Bush
Guide Bush

Stopper was deformed by impact, from which it is supposed cause is stiff or sliding failure between shaft and bush.
Seeing shaft(1), it is stained black.
Seeing carefully the other surface which the stained surface touches o-ring, the part stained black looks stripe pattern.
That shows the shaft often stops shortly while operating.
Checking the black matter more, it was from black carbon embedded inside the bush for lubrication.(Dry carbon prevents shaft from wear by touching shaft and lubricating it with melted carbon.)
It is supposed the melted carbon was mixed into moisture contained in supply air, and then adhered to the shaft surface. That caused stiff.

(2)Inside the Guide Bush
Inside the Guide Bush

【COUNTERMEASURE AGAINST CAUSE】
  1. Removing dry carbon bush
    →This is symptomatic measures by which lubrication function is inactivated, and risk of wear becomes higher.
  2. Removing moisture of supply air
    →No problem as the supply air is for facility line, and end-user has already installed a drier.
  3. Exchanging o-ring with dust seal.
    →The effect is uncertain because airtightness of dust seal is less than that of o-ring.

*****Maker's engineers were at a loss as they cannot find good solutions.

It is difficult to modify drastically far from the current structure, conditions for countermeasures are limited.

【Conditions for Countermeasures】
  1. Holding the same airtightness as o-ring, securing sliding performance under the conditions.
  2. Dry carbon lubrication is required due to need of wear resistance.
  3. Adding air drier is not acceptable for client due to additional cost.

【Final Solutions】

Taking consideration into the above conditions, it is concluded to find something replaced with o-ring.

As the result, we found "x-ring" as shown below,  and suggest maker to modify using "x-ring."

(Structure and Function of X-Ring)
Structure and Function of X-Ring

X-ring has higher airtightness than o-ring, and is hardly twisted by 2 contact surfaces.
Moreover, wear resistance will be improved because of lower contact pressure.
Cause of jamming possibly twist of o-ring, so it will be possible to solve the problem by replacing o-ring with x-ring.
In this way, it is supposed the problem can be solved under the current conditions.

【Result of Countermeasures】

Stoppage rarely occurs, client is satisfied.
Maker could save cost because of miner change.

Case2.SAMPLE FOR REPLACEMENT OF PRESS MACHINE AND MOTOR

<SAMPLE FOR REPLACEMENT OF PRESS MACHINE AND MOTOR>

SAMPLE FOR REPLACEMENT OF PRESS MACHINE AND MOTOR

The above photo shows main motor mounted on press machine.

【PROBLEM ON REPLACEMENT】

This motor is too old to ensure the compatibility with the replaced model.
The motor is discontinued DC motor, and data cannot be traced by motor maker with serial No.
Press machine maker also cannot ensure the compatibility.

Fortunately as motor maker had the replaced model, although different in dimension and construction, replacement can be considered.
But motor characteristics is required because it is main motor of press machine, and motor maker hesitate to accept the inquiry due to the risk of warranty.
(They insist you should ask press machine maker.)

【SUMMARY OF PROBLEMS】
  • Detailed specifications of motor are not clear.
  • This motor is HC motor, which requires DC conversion controller, but it is not clear if it is used for the replaced model.
  • The replaced model is different in dimensions, so the problems might occur in mounting dimensions and vibration.
【CONCLUSION AFTER REVIEW】
  • Judged no problem after comparing continued operation characteristics of replaced motor and old motor.
  • Confirmed with maker the existing controller can be used for the replaced model.
  • Judged no problem after checking mounting dimensions of the replaced model.
  • Gained end-user's approval for our explanation that we can recover immediately once any problems occur.

We cannot secure this work can solve the problems perfectly because data is not enough. But we concluded to replace the motor with motor maker's approval after discusstion in detail as much as possible.

Case3.SAMPLE FOR IMPROVED MACHINING TIME FOR MILLING PROCESS

PROCESSING:MILLING for Dent Part
WORK PIECE MATERIAL:S35C (carbon steel)

【CURRENTLY】

φ40 TA Type 2-FLUTE ENDMILL

(1)Drilling
Rev. Speed 1,000min-1
Feed 0.05mm/rev
Step 0.3mm
Depth 30mm
(2)Milling Traverse
Rev. Speed 1,000min-1
Feed 0.12mm/tooth
Cutting dept & edge angle ap15mm/ae35~40mm
【IMPROVED】

********Our proposal is changing Tool & processing

φ60 TA Type 5-FLUTE HIGH FEED ENDMILL

Milling Traverse
Rev. Speed: 900min-1
Feed: 1.0mm/tooth
Cutting dept & edge angle: ap1.2mm/ae63mm

Machining time : 4.5min.

【RESALT】

★Successful to cut machining time arround 50% off !!

SAMPLE FOR IMPROVED MACHINING TIME FOR MILLING PROCESS

Case4.SAMPLE FOR IMPROVED MACHINING TIME FOR BIG HOLE PROCESS

PROCESSING :MILLING for big hole drilling (Hole dia. : φ63 / depth : 360mm)
WORK PIECE MATERIAL :S50C (carbon steel)

【CURRENTLY】

φ40 TA Type 3-FLUTE HIGH FEED ENDMILL

Helical Hole Processing
Rev. Speed: 1,200min-1
Feed: 0.27mm/tooth
Cutting dept & edge angle: ap0.5mm
【IMPROVED】

********Our proposal is changing Tool & processing

φ60 TA Type 5-FLUTE HIGH FEED ENDMILL

(1)φ60 TA Type Drill (Hole Processing)
Rev. Speed: 6,400min-1
Feed: 0.14mm/rev. ,with 1 Step
●Processing Time: 1min.
(2)φ22 ,3-FLUTE ,Carbide Endmill (Side Surface Processing)
Rev. Speed: 1,200min-1
Feed: 0.1mm/tooth
Cutting dept & edge angle ap20mm/ae1.5mm
●Processing Time 2min.

Total machining time : 3min.

【RESALT】

★Successful to cut machining time arround 50% off !!

SAMPLE FOR IMPROVED MACHINING TIME FOR BIG HOLE PROCESS

Case5.SAMPLE FOR IMPROVED MACHINING TIME FOR DEAP HOLE PROCESS

PROCESSING :MILLING for deap hole drilling (Hole dia.: φ14/ depth :300mm)
WORK PIECE MATERIAL :S50C (carbon steel)

【CURRENTLY】

φ14 Gun Drill

Hole Processing
Rev. Speed 2,000min-1
Feed: 0.02mm/tooth
  Depth 300 mm, Stepping processing

Machining time : 10 min.

【IMPROVED】

********Our proposal is changing Tool & processing

(1)φ14 Carbide Drill (2D) (Rough Hole Processing)
Rev. Speed: 3,000min-1
Feed: 0.3mm/rev., Depth 300mm with Non-Step
●Processing Time: 2sec.
(2)φ14 Carbide Drill (20D) (Finish Hole Processing)
Rev. Speed: 3,000min-1
Feed: 0.25mm/rev., Depth 300mm with Non-Step
●Processing Time 24sec.

Total machining time : 26 sec.

【RESALT】

★Successful to cut machining time 9.5 min. off !!

SAMPLE FOR IMPROVED MACHINING TIME FOR BIG HOLE PROCESS

Case6.SAMPLE FOR IMPROVED MACHINING TIME FOR MILLING PROCESS

CURRENTLY CLIENT PROBLEM :

Many of the processed workpieces were thin materials such as SUS and titanium, and warpage occurred after processing...
Thus reducing the cutting resistance in cutting with small number of cutters, in order to suppress the warpage, however productivity is too low, and it had takes processing time much.

SOLUTION :

It is presumed that the cause of the warped is the high tool back force, and the cutter with a tool cutting edge angle (KAPR) 45 ° was changed to 70 °.
We selected a low-resistance chip breaker and aimed for stable machining even with an increase in the number of blades.
In addition, since stable machining was possible even if the tool diameter was reduced with respect to the cutting width, as a result the rotation speed and feed rate got improved.

RESULT :

Solving warpage problen and Productivity is 3 times UP!

Cutting Condition DOPENT CURRENTLY
TOOL Body(KARP) TEN09R063M22.0-04 (70°) Front Milling (45°)
Tool dia, Flute Φ63, 4 nos.flute Φ100, 3 nos.flute
Insert PNCU0905GNEN-ML Insert rectangle
(both face cutting)
Material of insert AH3135 Coating Carbide
Cutting Condition Cutting Speed Vc (m/min) 100 66
Feed/flute fz (mm/t) 0.15
Feeding Speed Vf (mm/min) 300 95
Cutting Depth ap (mm) 0.3
Cutting Width ae (mm) 60
Cutting Oil No Use
graph
Processing material : PLATE(SUS304) Machine : Vertical Machining Center

Page Top