Mechanical Engineering - Production Engineering - Discussion

Discussion Forum : Production Engineering - Section 4 (Q.No. 42)
42.
The stroke of a shaping machine is 250 mm. It makes 30 double strokes per minute. The overall average speed of operation is
3.75 m/min
5 m/min
7.5 m/min
15 m/min
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
10 comments Page 1 of 1.

Tarik said:   5 years ago
Answer should be 15m/min.

Rahul prajapati said:   6 years ago
Average speed is half of the cutting speed.

Vavg = V/2 = NL(1+m)/2000.

Akshay said:   6 years ago
Right @Dinesh.

Dinesh said:   7 years ago
Yes, right @Ajay.

But I think the answer is C because in question it asked for operation time, and operation occur only in forward stroke.

Mahesh said:   7 years ago
Yes, Agree @A.Jay.

The answer is 15m/min.

Ankur said:   7 years ago
1double stroke = 500 mm,
30double stroke = 15000 mm,
Therefore in 60 sec 15m/min.

Can it be the answer?

A.jay said:   8 years ago
The Correct answer is D 15 m/min. (Reference: S.K. Modal Production Technology notes) but at most places, Ans given is option C.

In simple language:
Average Speed = Total Distance/ Total Time.
Average Speed = (30 * 2 * .250)/1 because Total time is 1 minute.
= 15 m/min.
(1)

Ritesh Panchal said:   9 years ago
Here N = 30 rpm and L = 0.250 m.
So, LN = 0.250 x 30 = 7.5 m/min.
(2)

Professer said:   1 decade ago
If r=1 then the average stroke would be 250*30*(1+1=2)/1000.

Abhishek said:   1 decade ago
Average stroke = NL(1+R).

R = 1.

Average stroke = 250*30/1000 = 7.5 m/min.

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