CHINAPLAS 2014: Planetary cutter for small-bore medical tubing

Manufacturers of small-diameter medical tubing can automate cut-to-length operations and raise their productivity without worrying about cut-quality or particulate contamination with the new traveling planetary cutter (TPC) from Conair. Unlike a rotary fly-knife cutter that chops through tubing in one quick slice, the planetary knife rotates around the tubing, gradually penetrating the wall to yield a precise, square cut without the shattering, whitening or distortion that commonly occurs with other cutting methods. 

“A rotary cutter can automate inline cutting of many resins,” explains Bob Bessemer, Conair Sales Manager, Medical Extrusion, “but for other more brittle materials like crystal polystyrene, high-density polyethylene or highly-filled resins, processors concerned about getting a clean, square end cut had to resort to manual, off-line operations. The Conair TPC units diverts from that by making it possible to automate the cutting process of even difficult resins for improved productivity and lower cost without sacrificing quality.” 

Planetary cutting is not a new technology, but it has been used mainly in the manufacture of larger-diameter tubing and pipe. Today, however, it is possible to handle tubing as small as 0.080 inch (2.032 mm) in diameter, while holding cut-to-length tolerances of ±0.015 inch (±0.381 mm). 

In operation, the tubing exiting the extrusion puller moves through the cutter until it reaches the prescribed cut-off length. At that point, the servo-driven traveling table begins to move at the same speed as the tubing, which is clamped in place. The knife assembly begins to rotate and centrifugal force causes the knife blade to approach the tubing and make a lathe-like cut around the circumference of the tube. The cutter displaces material so cutting debris is essentially eliminated; distortion of the tube is avoided and a clean, square cut is created with no secondary trimming or deburring required. 

Cutting speed and force are controlled by adjusting the rotational speed of the cutter head. The faster it spins, the more quickly the knife penetrates the tube wall. Rotation is servo controlled for precision. Guarding is made of clear polycarbonate, allowing for full observation of the cutting process. The TPC is designed to allow quick cutting blade changes without removing product from the machine so that it is not necessary to stop and restart the extrusion line when a blade needs to be replaced. Front-mounted touch-screen control allows an operator to start and stop the cutter, adjust table travel velocity, blade velocity profiles and scale factors, as well as store process recipes for easy recall.

Conair Trading (Shanghai) Co., Ltd

Tel: +86-21 6760 1870

Fax: +86-21 6760 1871

Website: www.conairgroup.com.cn

Booth: W4J41