Even though tensile and compression testing machines are ubiquitous and used in almost every industry there is still lack of knowledge when it comes to purchasing the right machine. Given the range of products, the features and the variations in price buying one can be a bit overwhelming ans this becomes especially true for non standard applications.
One of the questions we get asked by our customers is whether to choose a manually operated machine, motorized one and if motorized, should we choose a machine with computer control and inclusive of data acquisition. So let’s look at this from a perspective of a spring manufacturer.
There are two factors which make this decision easier. The first and most obvious one is the cost. Manually operated machines are cheaper of course, then motorized and finally computerized. However, if you are looking at heavier springs which are used in train bogies or aircrafts, then motorized ones have to be used regardless of the budget. Imagine trying to put a compression force of 5000 kg on a spring (such as the ones used under the train bogies) with a hand wheel. Even with use of a gear train it’s hard work.
Once that is decided, the other factor which is important is the volume of testing. A spring manufacturer can spit out hundreds of thousands of springs a day. The question then is whether to conduct batch testing or 100 percent testing. Batch testing is where you pick a few samples from the batch, test them and if all are good you say that the whole batch is good. In such cases a manual machine would be acceptable. However, if one needs to test a couple of thousand springs a day it’s better to got for a motorized machine and reduce the burden of manual labour on the machine operator.
So we decided on a manual or motorized machine. Next step in the evolution is whether to get a computer controlled machine. These are machines operated directly from the computer and provide the testing output in the form of a force vs displacement graph. This helps visualize the behavior of the spring at every step of the way. Typically these softwares also provide a statistical report for all the tests, so min, max, standard deviation etc. Are available in the form of reports. Any large organizations where the report needs to be shared with the higher ups who only need an overview of the production quality, these machines are a good choice. Any new product needing data for validation has to be tested on such machines. In many cases the customer demand that the manufacturer submit the report online or in pdf format to avoid any possibility of manipulation. The only way to avoid this is to use a computerized machine.
In certain cases the product you manufacture dictates the type of machine, there are ASTM, IS standards which make the choice for you. However, for cases where its a non standard product, we hope this article helps you decide what’s best for you.