Testing of Functional Product Characteristics

School backpacks must withstand a significant amount of wear and tear— heavy books, a snack, and whatever else children need at school. They are carried and sometimes hung by their handles and straps. So that backpacks last multiple years, the handles and straps must be firmly attached. This example shows a backpack being tested. A clamp from ZwickRoell's product line of tools holds the backpack in the testing machine while a hook pulls on the handle. This ensures that the seams and plastic parts withstand wear and tear for many years.

Yogurt cups, beer crate, or water bottles— each type of packaging is stored for some amount of time in a warehouse and is stacked there. But how may layers of packaging can be stacked without breaking those on the bottom?

The question can be answered very simply by a testing machine. To find out, the filled or empty packaging is compressed individually or in a stack between the compression platen of the testing machine, measuring the maximum load capacity. The value allows us to determine how many layers can be stacked on top of each other.

But how can the packaging be improved? Typically, the mechanical characteristics should be achieved using the lowest material cost possible. To achieve this, an intelligent, constructive design is needed and the engineer must understand where the critical points of the container are. The testing machine is equipped with a video camera and the testXpert III videoCapturing+ option, which synchronizes the film sequence with the force travel diagram. It allows the engineer to analyze the deformation behavior of the packaging under any load and can optimize points that are truly critical.

Who hasn't encountered this problem? The creamer lid needs to close tightly, but still be able to be opened without a lot of effort. In a worst case scenario, the creamer doesn't pour into the coffee cup, but rather spills onto your shirt or blouse. To prevent this from happening, high-quality manufacturers test opening forces with a testing machine. The test sequence mirrors the exact same sequence as when a human opens the package. First the die presses in the lid and breaks the seal. Then a small hook opens the lid. The forces required are recorded by the testing machine.

Every car has many meters of low voltage cable inside. These cables run through the entire car and when installed, make contact with very sharp edges at times. The insulation of these cables must not be damaged. To measure this behavior, the automobile industry developed the LV 112 test method to determine the notch resistance of cable insulation.

The principle is simple. A cable is placed on a plate and electrically connected to a contact element. The test die has a extremely hard, high-strength wire, also electrically contacted, as the cutting tup. Using the wire, a load is applied to the cable until the electrical contact between the cutting tup and the cable's conductor is established. The force required for this is recorded by the testing machine. This offers a realistic assessment of the notch sensitivity of the cable insulation.

Synthetic windows must be able to withstand many loads and still close tightly over a long period of time. The corner stiffness of the window frame is one of the characteristics that is used as a characteristic control point. A defined support that enables frictionless movement of the leg of the test specimen ensures high reproducibility of the measured forces.

Syringes are manufactured in large batches and must meet high quality standards. One test measures the glide force and the activation force of a filled syringe. ZwickRoell offers the right fixtures for these tests, and these fixtures can be mounted on any testing machine. The testXpert III software controls the test sequence and automatically determines the results, such as the average friction force.

Many products are marketed in packages that must also perform a specific function. One example is a spray pump, which is used for expensive perfume as well as household cleaners. The window cleaner must be stored in the bottle, but must also be able to be sprayed onto the window in a forceful stream or as an atomized spray. The activation force must be tolerable for the user, and the dose must be high enough so that the user does not have to pump the handle too often. ZwickRoell's electromechanical testing machines assist here as well, to optimize the product and assist in quality control by measuring the activation force of various pump speeds. Subjective perceptions of quality are measured in this way.