When air- or pressure-based free extrusion of thermoplastic tubing for medical and nonmedical applications is not possible, melt extrusion assisted by tiny cylindrical rods called mandrels
Each caliber-specific mandrel
is turned to size to fit just inside a newly sized case mouth close to bullet diameter.
For different product diameters, a new timing screw and bullet (mandrel
) can be installed in minutes, while different product heights are accommodated by raising or lowering the machine with a turnscrew mechanism.
The cross section deformation degree without mandrel
or with different mandrels
is shown in Figure 7(b).
For other branches of industry using such mandrels
billets the container bushings from steel of the 5KhNM grade of 690 mm diameter were made, which had wall thickness 185 mm and mass 2.5 t , hollow billets of big nuts from steel 45 of 175 kg mass, etc.
The technology--the vacuum-steam-vacuum (VSV) process--involves using equipment that includes a mandrel
to apply vacuum and steam to a product.
The order included a Centurion PB 22-36 inch pipe bending machine with bending sets and mandrels
. In addition, CRC-Evans shipped another model PB 48-60 Pipe Bending Machine for arctic work in Siberia.
APC PTFE Natural Fluoropolymer Mandrels
feature a uniform, non-flaking coating which provides a smooth, anti-stick surface that can withstand 288oC continuous temperatures with excursions to 371oC.
The major component was the gearmotor supporting the mandrel
. It had to be the correct torque, size, and weight, have clockwise and counterclockwise rotation and low noise.
When the coil is ready for the next pass, the sleeve is supported by expandable mandrels
that are inserted into the open ends of the sleeve.
Contract notice: Achieving precision tubes of variable thickness drawn seamless mandrel
A line of medical-grade, precision polytetrafluoroethylene (PTFE)coated stainless steel or nitinol-forming mandrels
used to make stent delivery systems is available from Applied Plastics Co.