How to Find Actual RPM of a Sewing Machine?

With the technology advancement, now sewing machines come with control panel and LCD display. The machine shows its real speed on the real time. So, you don't need to measure the machine speed separately as it is already available for your need.

But the traditional sewing machine those come with a clutch motor, machine speed is not available. Sewing machine manufacturers define machine rpm (maximum level) in the machine label and manual. On the shop floor, sewing machines are not being operated at maximum speed by the operator. Normally, sewing operators run a machine at a lower speed than specified maximum speed limit. It is not even possible to sew a garment at maximum machine speed.

So, what is the average or maximum speed at which an operator runs his machine?

A sewing machine

There are two ways of finding the speed of a sewing machine. First, you can use an instrument, the digital tachometer or you can calculate the machines speed from the sewing time, seam length and machine SPI. In this post, I have explained how you can find your machine rpm when it is on work using the digital tachometer.

Digital tachometer
Digital Tachometer

To measure the speed level of the machine, a Laser Tachometer is very useful. Using this instrument you can take measurements from a distance. Laser tachometers work by pulsing a tight beam of light against the rotating element.

Method of using a tachometer

If you don't have one, you can purchase a tachometer from the Amazon store. After purchasing the digital tachometer, read the how to use the device instruction. Instruction will be available with instrument brochure.
  1. Select one sewing machine for which you want to measure the motor rpm.
  2. Affix a reflective tape (small area 1x1 cm) on the machine hand wheel. 
  3. Ask an operator to operate the machine. Power on the tachometer and keep laser beam direction perpendicular to the reflective tape. Or you can randomly choose a sewing machine which is running on the floor, without informing sewing operators and measure its speed. To do this you need to affix the reflective tape to all sewing machines prior to doing the test. 
  4. The tachometer will record maximum speed of the machine 
  5. Study and measure 5-10 records and calculate average speed. 
This way you can find operator wise and machine category wise average machine rpm. This rpm data can be used for different types of analysis.

Benefits of measuring machine speed

If you have knowledge of the average speed of the machines running on the floor, you can manage the machine productivity, and use that in operator training. You can estimate the time required for completing one operation cycle.

The first and foremost reason, you can find potential improvement areas on the shop floor. If an operator runs his machine at a lower speed than the average speed of the machine then he will obviously take more time in completing his task. Operator performance can be increased gradually by increasing machine speed.

Secondly, RPM is needed in calculating operation standard time when the PMTS method is used.

> Calculate sewing machine RPM using a mathematical calculation

Note: This post was originally posted on 17 Dec. 2011 and updated on Sept 2018.

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