CATRA
| Specifications | |
| Test Stroke | 0 to 128 mm |
| Test Cutting Speed | 0 to 150 mm/second |
| Test Load | 25N and 50N |
| Optional | 0 to 25N counter-balance weights for delicate blades |
| Max Depth of Cut | 50 mm |
| Overall Vertical Capacity | 105mm (including 50 mm of cut) |
| Size | 1700mm x 1800 mm x 2000 mm |
| Weight | 350 kg |
| Typical Test Time |
Plain Edge Blade : 10 minutes (60 cutting strokes) Serrated Edge Blade : 10 minutes (60 cutting strokes) |
| Standard/ Norm | ISO 8442.5:2005 |
| Typical sharpness measurements from this machine |
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For an independent assessment of the machine see "BLADE" magazine March 2004
CATRA has been involved in the testing of performance characteristics of blades for over 45 years. In particular the problems of evaluating the cutting ability have been studied using various manual and mechanical methods. This knowledge has enabled CATRA to design an automatic sharpness test machine that meets the requirements of consumers, manufacturers and standards organisations The need for such a cutting performance test is internationally agreed:
The International Cutting Test Standard BS EN ISO 8442-5:2005 Starting work in 1988 a group of specialists from various countries have developed a standard within the ISO Standards Committee for articles in contact with food. It specifies the detailed test method and sharpness specification for knives for the preparation of food. However, the test if ideally suited to other types of blades, including:
For more delicate blades such as razors, disposable surgical and medical blades CATRA recommends the Razor Edge Durability and Sharpness Tester
Testing of knife sharpening devices and systems
Not only can this system test knives, it can be used to test knife and blade sharpeners, by a clever system of testing and sharpening ( see below)
The system can also be used to measure the ease and abrasiveness of cutting various papers. By using standard blades and test cards made from the paper samples under investigation the machine will give very accurate performance figures, enabling paper processors to evaluate their cutting processes.
The principle of the test is simple. The blade is mounted in a position with the edge vertical and a pack of specially developed synthetic paper is lowered on to it. By oscillating the blade back and forth the blade cuts into the paper, the depth of the cut being the measurement of sharpness. The test media is loaded with 5% silica, which has a mild wearing effect on the blade edge. By repeating the back and forth motion, the further cuts are made, which wears the cutting edge. The measurement of cut depth at each subsequent stroke can then be plotted to produce a wear curve for each blade tested. The test produces two indications:
The test is designed for straight or nearly straight blades. However, specially modified machinery can be provided for circular or curved blades.
The test machine and control software is designed to operate on the industrial quality PC system built in to the equipment. The operating software interlinks with Microsoft Excel and Access to provide data analysis, reporting and database facilities, it has Windows XP capability. The software is optionally available with on screen information and reports in English, German, French. Spanish and Japanese
Specially formulated and quality controlled card with controlled Silica content of 5% supplied in: 10kg packs.......Thickness 0.31 mm >± 0.02 mm.....Weight 200g ± 10g/m²...Cut into Strips 10mm wide x 625 mm long
The CATRA Cutting Test Machine is generally as shown in the drawings below. The machine comprises of a rigid metal fabricated frame (Base & Cantilever) to which all major sub-assemblies are mounted. It is configured such that the blade to be tested is fixed, edge upwards, on a reciprocating table mounted onto the base of the machine whilst the test media (card) is applied, under load, onto the knife edge from the cantilever.
The blades to be tested can be easily clamped into the self-centering vice, which has a jaw design to compensate for blade thickness and taper in two directions. The centre line of any blade is therefore always the same datum; adjustable pillars support the blade and are used to set the attitude of the test portion of the cutting edge to as near level as possible. This design means that any length of blade can be accommodated, provided that the test portion is positioned over the vice jaws and is therefore supported.
The vice is mounted on a horizontal low friction slide which during the test is free to allow lateral float of the blade whilst cutting through the media, but returns to the fixed datum position for the beginning of each new cutting block. This slide is in turn mounted onto a horizontal table, which facilitates the longitudinal motion of the blade for cutting strokes. Drive to the table and therefore the blade is via a servo motor and lead screw arrangement, which allows precise positional and speed control over all or any part of the table's stroke. Therefore the test is carried out with a constant speed and motion envelope.
The test media (strips of card which are pneumatically clamped during cutting) is mounted in a holder with a capacity of 50 mm cutting thickness on a vertical low friction slide. Test load is applied vertically to the slide and therefore the media, by a calibrated weight. The method of lowering the media to the blade, together with the vice jaw design allows a full range of blade widths to be accommodated. Measurement of the amount of the card cut is achieved electronically. At the beginning of each new test and after each cut through the 'block' of media, the card is fed forward automatically by a pneumatic indexing system.
Operation of the machine is totally automatic (not manual version) except for the loading, setting up of the blade and replenishing the packs of cutting media. The machine functions are controlled by a microprocessor based unit, which switches electro-pneumatic devices and controls the motor under instruction of the resident program. This unit is in turn a slave to a host computer of IBM PC compatibility. The function of the PC is to provide the operator interface at the keyboard and to manage the test data, parameters, generate test reports and allow rapid comparison of current test data with the full database of previous reports. Test report are generated in Microsoft Excel and the data is stored in an Access database for easy future comparison and retrieval.
The flexibility of machine design and software allows the user to 'develop' their own testing programmes (not manual version). Using the purpose written software specially developed 'in-house' at CATRA, the machine is capable of carrying out fully automatic cutting and wear tests on a blade with very little operator intervention. Results are stored onto disk ready for analysis using the supplied software or import to other proprietary data analysis software. The test allows the blade to cut through a maximum distance 50 mm of card whilst the controlling PC logs the depth of card cut per cycle and the number of cycles. These tests can be repeated any number of times and can then be displayed in tabular and graphical formats, as well as determining the results in any form required, including the initial cutting performance (ICP) and the edge retention properties (TCC) as specified in the ISO Standard.
Optionally, a single or 3 axis load measuring platform can be mounted below the blade vice to enable measurement of some or all cutting forces. This is useful as an instrument to aid in the development of knife edges for example in the minimising of cutting forces. The additional load measuring package includes a load cell, all cables, computer interfaces and integrated software.
To test sharpeners the system can be operated in a different mode. By taking a particular standard knife blade and testing it on the machine up to a set number of cuts, then removing it from the machine, carrying out a resharpening operation using the sharpening unit under test and then returning the knife to the test machine, the performance of the sharpener can be gauged. It is normal for the above cycle to be repeated a number of times to evaluate the on going efficiency of the shapening or honing device. This then reveals a chart similar to the ones shown below. The technique can be used for measuring sharpening performance of the following devices and processes:-
Sharpening steels
Diamond and ceramic sharpening rods
Manually operated mechanical sharpeners with abrasive elements made of steel, carbide, ceramic aluminium oxide, silicon carbide or diamond
Electrically driven units with sharpening elements made of carbide, ceramic, aluminium oxide, silicon carbide, cubic boron nitride ( CBN or borazon) or diamond
Chemical, electro-chemical and other bulk sharpening processes
| The following are some of the companies/organisations have the CATRA cutting test machine within their facilities | |
| USA | Dexter Russel, World Kitchen, Buck Knives, Spyderco, W R Case, Cutco/Alcas, Canada Cutlery, Leatherman, Bettcher and 2 in an un- named plants |
| Italy | Fiskars Montana, Metallurgical materials laboratory in Maniago |
| Germany | FGW, J A Henckels |
| Spain | Madrid University, Arcos |
| Portugal | CATIM, ICEL |
| Switzerland | Victrinox/Wenger |
| UK | Richardson, Stanley Tools |
| Japan | Master Cutlery ( Global Knives) |
| France | Goutebarge |
and of course CATRA, we have 2, one for straight blades and one for circular blades, cutters and knives, which have tested knives for over 1000 companies Worldwide
Machines available for sale or short term rental for a one off project.
Or CATRA offers full independent and confidential testing services based on these machines.