How to calculate the period of the parallel sequential movement method?

The period of the parallel sequential movement method should be calculated according to the formula.

Formula: <>

Smooth: Parallel sequential movement mode processing cycle;

n: batch size of parts.

For the period calculation of the parallel sequential movement method, the calculation formula 1: t smooth = ti + (n-1) (t is larger - t is smaller) and the calculation formula 2: t smooth = n ti - (n-1) t is smaller.

Note: T smooth: parallel sequential movement mode processing cycle; n：

batch size of parts; ti: the processing time of the ith process.

The so-called parallel sequential movement method is a combination of sequential movement mode and parallel movement mode. It refers to the movement mode in which a batch of parts has not been fully processed in a process, and a part of the parts that have been processed is transferred to the next process for processing, so that the next process can be continuously completed with all the parts of the batch of moving mode.

The advantage of the parallel movement method is that the interruption time in the labor process is less than that of the sequential movement mode, and the production cycle of parts is shorter. To a certain extent, the space time of workers and equipment is eliminated, so that the space time of workers and equipment is concentrated, which is convenient for other work.

The disadvantage of the parallel movement method is that the organization is more complicated.

In the actual effect, when the single-room operation time of the previous process is less than or equal to the single-room operation time of the subsequent process, each part completed in the previous process should be immediately transferred to the subsequent process to be processed, that is, single-piece transportation in parallel moving mode.

The period of the parallel sequential movement method should be calculated according to the formula. Formula: <>

Smooth: Parallel sequential movement mode processing cycle;

n: batch size of parts.

Advantages: The interruption time in the labor process is less than that of the sequential movement mode, and the production cycle of parts is shorter; To a certain extent, the space time of workers and equipment is eliminated, so that the space time of workers and equipment is concentrated, which is convenient for other work.

Disadvantages: Organizational management is more complicated.

The formula for calculating the cycle time for this type of movement is as follows:

t = ∑t + n-1)tmax

Where: t: the machining cycle of a batch of parts moving in parallel;

tmax: The time per piece of the longest operation in each process.

For example, a batch of products, with a batch of 4 pieces, must be processed through four processes, and the time of each process is: t1 = 10, t2 = 5, t3 = 15, t4 = 10.

The processing cycle is calculated by parallel movement.

t=(10+5+15+10)+(4-1)×15=85

The simple moving average method refers to the use of arithmetic mean to calculate the moving average of each group of data formed by the continuous movement of the moving period, and use it as the value of the next period.

The formula for calculating a simple moving average is as follows:

ft=(at-1+at-2+at-3+…+at-n) where n--value for the next period;

n--the number of periods of the moving average;

at-1 -- the actual value of the previous period;

AT-2, AT-3 and AT-N represent the actual values of the first two periods, the first three periods up to the first n periods, respectively.

(1) When the single-room operation time of the previous process is less than or equal to the single-room operation time of the subsequent process, each part completed in the previous process should be immediately transferred to the subsequent process for processing, that is, single-piece transportation in parallel movement.

2) when the single-room operation time of the previous process is greater than the single-room operation time of the latter process, then the parts that are completed on the previous process are not immediately transferred to the latter process to be processed, but wait until the moment when the latter process can be continuously processed, and then all the parts that are completed are transferred to the latter process, so that the intermittent equipment downtime of the latter process can be avoided, and the scattered downtime is concentrated and utilized.