PVC, PP & Plastic Products #5141569

Commercial tubing & pipe are produced in both the seamless and welded process. Seamless starts with forged hollow bar while welded (also known as "as-welded", "sunk" or "CDOD Tubing") starts with flat strip stock. The seamless process accommodates very heavy wall or high pressure applications but is expensive and tends to have concentricity variances. As-welded tube will have the residual weld bead of metal protruding into the ID of the tubing. The ID will be rough since the material is not drawn over a mandrel.

Shaped tubing refers to tubing that is not round (circular) in form. Frequently, applications involve some type of stainless steel support for a product, a path or race for fiberoptics or other smaller components, or a dispensing application. Depending on requirements detailed by the customer, shaped tubing can be made stronger in some directions in a similar manner to the concept of an I-beam. All tubing drawn into shapes has to be formed through custom manufactured dies and subsequently straightened though specially formed tooling for straightening profiled tubing. In some cases, customer requirements result in a modest engineering fee for the design work associated with developing a method to form the tube. Vita Needle supplies shaped tubing in a variety of alloys, most popularly in 304 or 316 stainless steel. However, all alloys that Vita Needle produces can be drawn into shapes provided the shape is capable of being formed.

Certain applications demand seamless stainless steel tubing for critical functions. Often, seamless tubing is required for petrochemical, gas or nuclear applications where high pressures and exposure to corrosive environments are the norm, or if the tube's wall is too thick to be rolled and welded. Seamless tubing is manufactured by repeatedly drawing a forged hollow bar through a series of smaller dies. No welding takes place at all during the process, avoiding microscopic changes in the grain structure of the tube. Vita's unique tooling and setup capabilities allow us to produce small runs of stainless small diameter seamless tube in a matter of a few weeks, not several months. We also offer competitive pricing on larger quantity seamless tube if required. Coils, straight lengths or fully finished fabricated parts are all within Vita's capabilities for seamless tubing. The majority of Vita's seamless tubing is custom made, except for standard commercial grade sizes which can be found on our commercial tubing page. Additionally, Vita stocks millions of feet of standard and non standard welded and drawn sizes, if this method is acceptable for your application.

A skive is a slice along the long axis of a tube or wire that leaves a thin layer of tubing (or wire) remaining after completion. Typically as the end of the desired cut length is approached, the skive gradually rejoins the remaining tube over a large radius transition zone. The image below depicts a skived stainless steel tube. They are popular for balloon delivery and retraction applications, and can also be found on tubes for the purposes of product alignment with another piece, or to bottom out a product for secondary welding. Vita has a proprietary method to produce skives with close tolerance requirements, and can even break the heels and radius the tips of skives if required for the application. Finishes along the cut surface of the skive can also be improved using our proprietary manufacturing methods.

Vita Needle cuts and deburrs tubing to customer specified lengths and tolerances utilizing several methods. Our most frequently used cut and deburr methods include: Abrasive: Relies upon a spinning cutoff wheel, typically aluminum oxide, to cut tube and a secondary deburring process is utilized after cutting is complete.Electrochemical (EC or ECM): In simple terms, a combination of abrasive and reverse plating by incorporating electrical current into the process in order to cut and deburr tube simultaneously.Electrical Discharge Machining (EDM): Electrical current creates a series of high frequency discharges that erode tubing material in a burr free manner.Supported shear: Custom dies and related mechanical supports are used to precisely cut tube free of burrs.

Welded and drawn is the preferred tubing choice in terms of economy, lead time and tolerancing compared to seamless in most instances. Many demanding applications call for the T.I.G. welded and plug (mandrel) drawn method, used by Vita Needle for over 85 years!