Here is a quick checklist that can help avoid questionable results due to slippage of the specimens in your tensile tester:

·      Use the Grips for the purpose they were designed for

·      Know your fibre type! Its characteristics will affect what grips you need to use, gauge length and pressure that will be required to perform the test.

·      Make sure the maximum load capacity of the grip is suitable for the specimens to be tested.

·      Ensure the jaw faces are suitable for the forces that are going to be applied during the test. 

Note: Rubber faces will degrade quickly at higher loads.

·      The faces should not be too aggressive for the type of specimen such that it causes premature failure.

·      Make sure the specimen is centrally mounted and fully inserted into the grip faces.

·      Correct maintenance of the grips whether they are manual, pneumatic or hydraulic.

·      If in doubt ask your supplier for advice.

General Maintenance

·      Check all fastenings are secure and in good order no loose or wobbly parts.

·      Check they are moving freely / lubricated also free of loose fibres and any debris.

Manual grips

·      Do not over tighten them.

·       Make sure all catches lock securely.

               Pneumatic Grips

·      Ensure the compressed air supply is clean and dry; that means regularly emptying the relief valve to drain off any moisture regularly.

·      Adjusting the pressure to be appropriate in order to prevent jaw breaks but not exceeding the maximum operating pressure.

·      If you suspect air leaks get them checked/serviced. 

Hydraulic grips

·      Check your fluid levels.

·      Look for any signs of a leak.

·      Note pressure level required to give a good break and apply this consistently for each specimen.  

Jaw faces (applicable to all grip types)

·      Check the faces for wear and tear before you fit them into your grips.

·      Again you need to use the correct faces for the product you are testing.

·      Please use the locating pins provided with the grips.

·      Replace the rubber faces when they show signs of wear; badly worn or uneven faces can lead to slippage, premature failure of specimens and incorrect test results.

·      Clean off any off any residual lubricants/ finishes’ that may have built up during testing of some specimens.

Yarn / cord testing using bollard grips

·      Check the cord path is not worn or damaged and free of any residual build up from the yarn or cord.

·      Set up the gauge length from nip point to nip point.

·      Surfaces of clamp faces can become polished and cause slippage.

·      Aggressive faces or too much pressure will cause jaw breaks.

Nose pieces

·      Make sure they are tightened correctly but again not over tightened, which may lead to twisting of the load cell and permanent damage of the load cell.

·      Know the rating of your grips and don’t assume the nose piece size dictates the load capacity.

Compression - Puncture Testing

·      Check probes for damage and/or signs of wear as this will influence the way the probe penetrates the fabric under test and affect your results.

·      After attaching the probe to the nose piece check for alignment to the lower clamping unit to ensure the probe passes through the aperture freely.

·      Check the fabric in the lower clamping unit is clamped evenly with sufficient pressure to prevent slippage during testing. 

In the lead-up to the holiday season in Luxemburg, toy safety was the subject of a lot of media attention.  Luxembourg does a lot of importing from the Far East then re-exports these goods throughout Europe,  so it is vital that the items are safe. ILNAS is the Luxembourg governmental department for standardisation, somewhat similar to ASTM or BSI, and are responsible for making sure all products coming in the country meet Luxembourg (European) regulations. ILNAS have a laboratory that does Market Surveillance and testing and they recently bought one of our machines to check that toys conform to EN 71 Part 1 for tensile and compression strength; this is part of a whole range of tests that are required to be performed on these toys.  This laboratory and their work was featured in newspapers and on tv. Click here to preview the tv news report.