Posts Tagged ‘engineering design and testing.’

Product Testing or How do I make sure the Product will do what I want?

November 23, 2008

Product Testing or How do I make sure the Product will do what I want?

The success of your product and your company will depend largely on how well your product performs. Does it do what you want it to do and, perhaps more importantly, does it do what the buyer expects it to do? While the latter portion of this question deals with marketing, advertising and how you represent your product, the first portion is at the crux of this article.

A critical segment of your product must be the specification. This specification will describe not only what criteria you want the design to adhere to, but it should also include some consideration of the reliability and durability of the product. What is the difference? Reliability is simply how consistently the product performs its key functions. If a ball only bounces every third time you use it, it is not reliable. Durability is an indication of how long the product will perform its required functions. Back to the ball example, if the ball only bounces three times and then bursts, it is not durable (unless three bounces was your design goal!!).

In general then you must evaluate your product to determine if it meets the requirements that you had intended for it. In addition, in many instances, there will be government or organization mandated tests that must be passed. For example, UL (Underwriters Lab) certification is required for many consumer products. UL defines the specific test and how you must conduct it. Typically you would have these tests completed at a testing facility which meets the UL testing requirements. So, do your research on government and other organization tests to which your product must be submitted. Note that these tests will not typically test the functions you are concerned about. These tests are more focused on such items as flammability, electrical grounding, can a child swallow it, and so on.

Let’s talk specifically now about evaluating your product for those characteristics that you want your product to do. Typically product development professionals refer to a products’ “fit, form, function, reliability, safety and durability”. You will want to create and conduct tests which will validate your product in each of these areas. To do this you first need to define that feature that you wish to test. Let us say that your product is a new garden hose sprayer. Let us go through each of the characteristics we noted above and relate them to the garden hose sprayer:

Fit: You would be concerned with how it fits the typical hand. You may set up a test where you have a number of people (a mix of genders and sizes) pick up and hold your sprayer and evaluate it against a number of criteria i.e. is it too heavy, is the surface too rough, and so on. You can also do this using computer generated ergonomic models.

Form: Once again perhaps a mixture of objective and subjective measurement would be used here. Does it look sufficiently aesthetic? Is it the right color? Does it look like a garden sprayer or does it look like a hair brush?

Function: Here is where we get a little more objective. Does the trigger adequately control the spray volume? Does the control knob for varying the spray type work well? Does it fasten tightly and easily to the hose?

Reliability: Now we get much more objective. How consistent is the trigger’s operation? You may design and fabricate a machine that will repeatedly actuate the trigger. This machine would also measure the force required to actuate (does it change with repeated actuations?) and the amount of spray (does it decrease with repeated actuations?). Note that this same test can also cover many of the questions regarding durability.

Safety: This is very important. Does the users’ finger get cut by the edge of the trigger? Is the sprayer capable of sending such a high pressure jet of water that it penetrates your skin?

Durability: This product will be exposed to the weather most of the time. You will want to know if it fails to function when it is at 120 degrees F (a common temperature for a yard tool to reach if it is lying in the sun for some period of time). The make up of this test may be using the same test fixture you made above for actuating the trigger and placing it in an environmental test chamber. These chambers are typically something you will not have sitting around. You will have to engage the services of a testing laboratory to complete this. This same lab should be able to perform a UV (ultra violet) light test. Your sprayer will be sitting in the sun a lot. You certainly want to know if it falls apart after being exposed to sunlight for two weeks.

A lot of thought and research needs to be placed into defining these tests. You will find that a good testing lab will be instrumental in this work. You will also want to document the means by which all of these tests where conducted, the equipment used and the results. A good testing lab will do all of this as a matter of course.