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| VACUUM WORKHOLDING EXPERTISE Thame Workholding has built up a wealth of experience providing standard and special workholding solutions using vacuum to all sectors of industrial manufacturing for over 25 years. In particular the Aerospace, Medical, Motorsport, Electronics and Precision Sub-Contracting industries have many successful working vacuum applications supplied by Thame.  Angle Tilting Vacuum Chuck holding replacement hip cup. Vacuum workholding is a highly effective technique for holding thin or irregular shaped or non magnetic parts. Although parts with a large surface area are ideal, as the holding force is also large there are techniques for holding small parts as well. Vacuum workholding can be applied in Milling, Turning, Grinding and drilling applications. STANDARD PRODUCTS
. . . . . . . . . . VACUUM WORKHOLDING - HOW DOES IT WORK? On all surfaces of an object there is an even pressure due to the surrounding atmosphere of approximately 1 bar (10.9kg per square metre or 14.5 pounds per square inch). Using a vacuum pump, the air underneath the component is sucked away, so that the pressure load on these lower surfaces is partly removed; the clamping or holding force results from the difference in pressure between the upper and lower component surfaces. The amount of one-sided pressure is dependent on the amount of under pressure or vacuum generated. Modern vacuum pumps reach a vacuum of approximately 990mbar (20mbar absolute or 98% of the atmospheric air pressure of about 1 bar.) Using this theoretical example the pressure remaining on the lower surface is approximately 20mbar, the material is held down by the difference between the upper and lower pressure. The weather and position above sea level of the vacuum application will have an effect on the actual clamping force obtained for a specific application. VACUUM WORKHOLDING - WHAT HOLD DOWN FORCE CAN I ACHIEVE? The clamping force on a component is proportional to the surface area, therefore, for a component size of 20cm x 40cm and vacuum of 0.8 Bar, the clamping force can be calculated: (1 Bar = 100kN/m² or 14.5lbs/in²) Clamping force in kN/m² is 0.20m x 0.40m x 0.8bar x 100kN/m² = 6.4kN Clamping force in lbs/in2 is 7.87” x 15.75” x 0.8bar x 14.5lbs/in² = 1437.8lbs MACHINING GUIDE LINES When using vacuum to hold parts it may be necessary to review the machining process to suit this style of workholding. Vacuum workholding is less effective on small size components therefore rather than machining individual workpieces plan to machine several parts from a larger size of raw material. Cutting tool technique when using vacuum fixtures tends to mean using smaller diameter cutters, increasing spindle speeds, feed rates and ramping rather than plunging. Cutting forces need to be considered and on thicker material it may be necessary to employ the use of stops directing the cutting tool pressure toward the stop. Unsuitable or blunt tools increase cutting force pressure and should be avoided. APPLICATIONS AND ADVANTAGES We offer Vacuum Workholding for the following:-
Vacuum workholding offers the following benefits:-
Downloadable PDF: Vacuum Workholding (1.3Mb) |
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| Field End, Thame Road, Long Crendon, Aylesbury, Bucks HP18 9EJ England T: +44 (0) 1844 208050 F: +44 (0) 1844 201699 E: sales@thameworkholding.com |
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