Acme lead screw assemblies are the preferred choice of many when it comes to linear motion applications, partially because they're very flexible, coming in "many flavors" so to speak. One example of this is simply how many material combinations are available between the screw and the nut.
Acme lead screw assemblies are the preferred choice of many when it comes to linear motion applications, partially because they're very flexible, coming in "many flavors" so to speak. One example of this is simply how many material combinations are available between the screw and the nut. To name a few, nuts are available in Delrin (acetal), PEEK (polyether ether ketone), PET-P (polyethylene terephthalate), PAI (polyamide-imide), bronze, steel, and stainless steel. Helix also makes screws in a variety of alloy and stainless steels as well. Combined with our array of nut materials that means we can deliver a combination just right for your application. To further fine tune performance, screws can also have different coatings such as black oxide or PTFE.
At Helix, we specialize in fabricating lead screws with 300 Series stainless steel. This family of stainless steel resists corrosion and maintains strength over a wide temperature range. If your application is going to be utilized in more extreme environments, a stainless steel lead screw could be just the right solution for you.
Here's a closer look at some of the benefits of electing to use a stainless steel material for your acme lead screw:
- Corrosion Resistance: Stainless steels offer resistance to corrosion to varying degrees by way of their chromium content. Stainless steels develop a tightly bonded layer of chromium oxide that protects the surface and underlying material from oxygen diffusion. The chromium oxide layer can even “heal” itself if scratched so long as there is sufficient oxygen present. Harsh environments like automotive, aerospace and construction applications are ideal for this variety of screw.
- Temperature Resistant: Not only are stainless screws tough and durable, they will maintain these properties at very high and very low temperatures.
- Easy to Manufacture: One big benefit of acme lead screws in general is their comparative low cost when compared to other technologies. One of the reasons Helix screws are less expensive to manufacture is that they are produced by a rolling process which is much faster than machining or grinding. Stainless steel is able to be rolled which allows us to take advantage of the cost benefit of the rolling process. Stainless steel is also able to be cut, welded, and machined with relative ease.
- Cost: Not only are stainless steels easy to manufacture and fabricate, but when you consider total life cycle costs, it's this type of material that often scores best. That's right, compared to other materials; it's stainless that often wins the life cycle cost comparison.
- Hygienic: Stainless steels are also more easily cleaned - meaning that they are generally easier to maintain than other types of materials.
Now that you know some of the general benefits about selecting stainless over other materials, let's take a closer look at some of the more popular 300 Series stainless steels that we use at Helix and their properties:
- 302 Stainless: A common chrome-nickel stainless that is also heat resistant. It offers a tensile strength of 100,000 psi and a hardness Rockwell of B85, making this material ideal for applications ranging from food and beverage to sanitary.
- 304 Stainless: The 304 stainless steel is said to be the most popular and most widely used of all stainless steels. It's non-magnetic and versatile, offering a lesser carbon composition to minimize carbide precipitation. It's most commonly used in extreme high temperature applications. It's also resistant to corrosive acids. Additionally, 304 Stainless has a tensile strength of 95,000 psi and a hardness Rockwell of B80.
- 316 Stainless: An ideal material for use in the chemical, food and oil and gas industries, 316 Stainless has a low carbon content to avoid carbide precipitation. It adds molybdenum and offers a slightly higher nickel content than other types of 300 Series stainless steels and features a tensile strength of 90,000 psi and hardness Rockwell of B80.
To review, when it comes to acme lead screw assemblies, the material options are plentiful, from PEEK to bronze and beyond. But the application that you're working on should always dictate the type of material you select. For more extreme environments, a stainless steel acme lead screw may be the right option for your linear motion application and something that you should consider.
So what about the nuts? In case you're interested, here's a reference guide that we've put together describing the various types of material we use when manufacturing Helix lead nuts.