An extension spring is a part that captures energy and develops force used to execute an action. The “initial tension” is created during manufacturing when the wire is rotated backwards during coiling. When you pull the spring apart, you are undoing the rotation, which develops force or initial tension.
Extension springs are used in a wide variety of applications where a precise amount of force is required at a certain deflection. They can range dramatically in size (1/2-inch to 50 feet) and in the force they create (ounces to thousands of pounds). To illustrate the point, they can be pulled an inch or 100 inches.
Extension springs are used to retract aircraft landing gears and to tether equipment to oil rigs in off-shore applications. They are used on Class 8 heavy trucks as hood-assist springs to safely hold the hood in place for engine maintenance. Other examples include specialized springs implanted in roads as anti-terrorism barriers to provide security for military buildings and other potential targets.
If you are looking for industry-leading expertise for extension springs, look no further than MW Industries. We manufacture extension springs ranging from 0.008 inch thickness—which is approximately the thickness of a single hair strand—all the way up to ¾ inch bar and wire. The bigger the bar, the greater the extension spring force.
One of the unique attributes of our Atlantic Spring business is that it maintains stock on numerous alloys. The advantage to engineers is that if a couple of prototypes are needed, our in house stock gives us the ability to make them for you in a very cost effective way.
We stock everything from steel to exotic materials such as Inconel®, Hastelloy®, bronze and beryllium copper. We even make extension springs out of tantalum which costs twelve hundred dollars a pound! We also manufacture springs out of Beta-C, a titanium alloy which is both hot and cold workable and develops forces that you can’t get from steel.
Extension Spring Manufacturing
There are two ways of making extension springs. The older, traditional way involves hand coiling on a lathe. Wire is fed into a catch, coils are formed by hand, then the wire is cut at the end. After the coiling, hand-forming is required on the spring ends to meet design needs. It is an accurate, reliable and cost-effective way of making extension springs.
The second method of coiling is automatic and is done on large CNC lathes. Wire is fed into the coiling machine and is wound to precise specifications. It is most appropriate for larger run sizes and when tight tolerances are required.
Rapid Prototyping / Design Assistance
Our solutions approach is not limited to manufacturing. Working with your team, we will use the application specifications to determine how to best design and process extension springs using state-of-the-art software and years of expertise. Our engineers take into consideration:
- Wire dimensions and winding
- Metal materials
- Production process
- Hardening or heat treating
- Corrosion resistance
- Quality assurance
- Packaging, inventory and delivery
An extensive amount of research is done before we even begin the spring manufacturing process. The first thing we review is the customer’s specifications. We make sure that we have the right material for the specification. Then we make sure that the operation sequence is detailed specifically and that all of the tolerances are listed.
Our quality system is very structured and second to none. We go through an extensive “first-piece” requirement for each operation. We make an initial part off the coiler and then run it through multiple processes—grinding, stress relieving, setting and inspection. If it is determined that the spring is not in the center of the allowable range, the entire process will be repeated. Finally when the inspection department feels that the spring is in the center of the range, permission is given to coil the spring.
Inpection & Certification
The Inspection Department at our Atlantic Spring facility is one of the largest in the industry, with more than 12 scales to check springs and conduct extensive testing of every order. Depending on the application, we conduct up to 100% inspection to make sure that each customer receives a quality product.
Forming the hooks an extension spring requires is not easy. Without a highly-skilled workforce, formulating a safe and accurate spring, you will most likely end up with a part that fails. Our broad material and equipment expertise, coupled with our skilled technicians, means we have all of the right capabilities to deliver solutions that meet our customers’ performance goals.
MW Industries’ business units have earned the most stringent manufacturing certifications available. That’s why 23,000 customers, across every industrial sector, in more than 35 countries turn to MW Industries to solve their spring challenges.
Lastly, our customer service, engineering, production, delivery and follow through work in tandem to prove to our customers on a daily basis that MW Industries is their best choice for extension spring manufacturing.