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Pre-Straightened Wire for Medical Devices - Introducing SLT® (Straight Linear Torque) Wire

Straight Linear Torque (SLT®) Wire is a custom engineered solution from Fort Wayne Metals. The wire is designed to be an extremely straight, off-the-spool solution that removes the need for polishing and reduces the build time for creating new devices. SLT® Wire is provided in four different types, meaning it is accessible to any kind of manufacturer.

AZoM spoke to Eric Dorman, Product Manager at Fort Wayne Metals, about their expanded SLT® Wire range, the different benefits it delivers to manufacturers and its wide range of medical uses.

Please could you introduce our readers to your newly expanded SLT® Wire line?

SLT® Wire, or Straight Linear Torque Wire, engineered by Fort Wayne Metals combines excellent straightness, directly off the spool or when cut to length, with excellent torque transmission from the proximal to distal tip. SLT® Wire is processed to eliminate the need for further straightening operations, it arrives ready to form or grind.

Fort Wayne Metals offers our SLT® Wire product in four different types.

  • Type 1 SLT® Wire:  Provides a much larger, than as drawn, wire cast directly off the spool with a straightness variance of 1” arc in a 12” piece.
  • Type 2 SLT® Wire:  The newest addition to the SLT® Wire product line. This value-add product eliminates the need for mechanical straightening and gives you a rotary mark free surface with a straightness variance of .118” in a 12” piece.
  • Type 3 SLT® Wire:  Comes ready to use by eliminating the need to mechanically straighten and heat treatment of the wire prior to grinding, with a straightness variance of .02” in a 12” piece.
  • Type 4 SLT® Wire:  Our premier SLT® Wire that features excellent 1:1 torque response in conjunction with being ready to grind upon arrival, with a straightness variance of .01” in a 12” piece.

Comparing rotary straightened wire (top) and SLT® Wire (bottom) underneath a scanning electron microscope shows that SLT® Wire is smoother and straighter.

Comparing rotary straightened wire (top) and SLT® Wire (bottom) underneath a scanning electron microscope shows that SLT® Wire is smoother and straighter.

What motivated you to enhance your SLT® Wire line?

Our motivation behind expanding the product line was driven by customer demand.

Our customers wanted a product that combined the excellent straightness of our Legacy SLT® Wire with a price point that would satisfy their project requirements. From there, we researched our customers’ needs and were able to develop the expanded four types of SLT® Wire we offer today.

What are the differences between the four different types of SLT® Wire that Fort Wayne Metals offer?

All four types of SLT® Wire share the common advantage of eliminating the need for straightening the wire upon receipt from Fort Wayne Metals.

There are three distinct characteristic differences as you move up the SLT® Wire line; straightness, grindability, and torque transmission.

What benefits does pre-straightening the wire bring to your end users?

Pre-straightening the wire eliminates manufacturing process steps, reduces set-up time, and provides a consistent and repeatable starting point.

An additional benefit of our SLT® Wire product line is the elimination of rotary spiral marks. Spiral marks are found on the surface finish of traditional rotary straightened wire or in the rotary straightened step performed by the customer and will sometimes require a polish to remove these surface defects. SLT® Wire comes with a surface free of these defects and is ready to use - eliminating the need to polish the wire.

How do you process your SLT® Wire to ensure that it does not deform when its width is reduced?

Our proprietary thermo-mechanical straightening process was explicitly engineered to optimize the combination of temperature and time.

The SLT® Wire process delivers a uniform grain structure throughout the wire allowing ideal grindability for those challenging taper and profile grinds.

What characteristics of wire are most important for neurovascular guides or for endoscopy? Which type of SLT® Wire is most appropriate for each of these applications?

A great question and one that varies depending on each application and procedure need.  The key characteristics to consider for neurovascular guidewires and endoscopy are,

  • Core diameter: larger wire diameter will give you greater rail support and strength, improved torque.  Whereas smaller diameters will increase flexibility and trackability through the vessels.
  • Core material: this influences the guidewires flexibility, support, steering, and push-ability.  The higher the tensile strength of the wire the more column strength and torqueability.
  • Core tapering and grinding:  this will influence the tracking, ability to maneuver and navigate the twists and bends in the vascular system.  Long, gradual grind/tapers will bend easier around turns but will not have as much support as a short grind/taper guidewire.

Neurovascular guidewires often have challenging and deep grinding profiles, in some cases up to 95% cross sectional area without additional heat treatment of the wire, this is where SLT® Type 4 Wire is ideal for use.

SLT® Type 3 Wire can accommodate up to a 90% cross sectional area grind/taper in spring and hard conditions.  Any application that requires a grind or taper profile should consider either SLT® Type 3 or SLT® Type 4 Wire.  Applications that do not require a grind or taper grind should consider using our SLT® Type 1 or SLT® Type 2 Wires, these are designed more for wire forming applications.

What other applications is your SLT® Wire line designed for?

Fort Wayne Metals' SLT® Wire is used in many different medical applications. The list is huge and varied including devices and components such as stylets, micro and suture needles, surgical staples, mandrels, coils, stents and dental probes.

Additionally, the wire can also be used as a component of devices such as those used for breast tissue biopsies.

If there is a need for a wire with excellent straightness, grind/tapering requirement, spiral mark free surface finish, or a 1:1 torque demand than SLT® Wire can support you.

SLT® Wire can be used in medical stents

SLT® Wire can be used in medical stents

How easy is it for manufacturers to process your SLT® Wire?

SLT® Wire has been engineered specifically to reduce production steps in your operation.

Whether you just need basic wire that will eliminate the need for straightening and reduce machine downtime (SLT® Wire comes ready to be used straight off the spool, or cut to length, and with a great degree of straightness using ASTM F2819).

A premium straightened wire that will not deform during deep taper grinding (Type 4 SLT® Wire is designed for a deep taper grinding up to 95% of the cross section area) or anything in between, SLT® Wire will outperform the standard round wire you’re currently using.

Does Fort Wayne Metals offer consultations on which type of wire would be most appropriate for your customer’s applications?

Absolutely. Our website is a great place to start.  However, we realize that even the best website can only answer so many questions.

If you can’t find what you’re looking for (or don’t have time to go searching), please feel free to get in touch.  No matter where you are in the world and what language you are most comfortable with, we try to make contacting us easy.

You can call our global headquarters, located in Fort Wayne, Indiana, directly at +1 260 747 4154.  From there we will connect you with the appropriate Customer Service Associate in addition to your local area representatives around the globe.

About Eric Dorman

Eric Dorman

A 28-year Fort Wayne Metals veteran, Eric Dorman is on a level of unmatched experience and expertise. While working at the company, Eric pursued a degree from Indiana Wesleyan - graduating Magna Cum Laude, with a bachelor’s in Management - and then went on to earn his master’s of Business Administration from Taylor University.

Throughout his extensive history at Fort Wayne Metals, Eric has held numerous positions of varying responsibilities, including: Product Manager (four years), Plant Manager (eight years), Diamond Die Manager (two years), Shift Supervisor (two years), Customer Service Associate (three years), Production Scheduler (two years), diverse Production Associate Roles (seven years) – employing all of his accumulated knowledge and capability in his current position as Vascular Therapy Product Manager.

Eric’s wide breadth of roles at Fort Wayne Metals provides him with a unique perspective and ability to aid each customer with an overall solution to meet his or her specific material needs.

Disclaimer: The views expressed here are those of the interviewee and do not necessarily represent the views of Limited (T/A) AZoNetwork, the owner and operator of this website. This disclaimer forms part of the Terms and Conditions of use of this website.

Jake Wilkinson

Written by

Jake Wilkinson

Jake graduated from the University of Manchester with an integrated masters in Chemistry with honours. Due to his two left hands the practical side of science never appealed to him, instead he focused his studies on the field of science communication. His degree, combined with his previous experience in the promotion and marketing of events, meant a career in science marketing was a no-brainer. In his spare time Jake enjoys keeping up with new music, reading anything he can get his hands on and going on the occasional run.


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