If you need an acme screw thread, choosing between thread rolling and thread grinding can be difficult. After all, each process benefits applications in different ways. If you’re struggling to choose an option for your acme thread design, the following considerations can help you make a decision.
Thread Rolling
Thread rolling rotates a hardened steel die, pressing it against the surface of a cylindrical blank. The blank rolls against the threads of the in-feeding dies, displacing materials to form the root of the thread.
This process produces strong acme precision threaded rods, perfect for applications that need improved strength and fatigue resistance. Instead of cutting against the natural grain of the metal, thread rolling re-forms and hardens these structures. There are no sharp corners in the thread’s root, nor tool marks on the thread’s flanks. They also have a higher resistance to stripping.
This process is often recommended for several reasons. Thread rolling is the most cost-effective method for standard acme thread design. (At The PST Group, for example, we have an extensive inventory of thread rolling die. Unlike most acme nut suppliers, this means we can guarantee a quick turnaround.) Rolled material is also stronger than ground material because the rolling process isn’t chipping or removing any of the raw materials. However, this process is not always possible, due to part design or the acme thread design.
Watch our video below about acme thread rolling
Thread Grinding
If you need acme screw to meet custom backlash requirements, thread grinding is a better option. Thread grinding utilizes a CNC machine with an abrasive grinding wheel to form threads. This process produces tight-tolerance acme precision threaded rods, perfect for applications with unique part geometry or where a custom fit is required. Thread grinding also allows for threads to be cut into high hardness materials as well. Unlike thread rolling, there is no special tooling required, making thread grinding ideal for low-quality or prototype manufacturing lots. PST engineers have already helped several customers utilize thread grinding to provide custom solutions for their applications.
Take, for example, an existing PST customer that came to us with an application used in a flat actuator of a single engine aircraft. Cost and weight were the driving factor for this project, so the decision was made to use an acme screw assembly instead of a ball screw assembly.
The requirements for this acme screw thread are strict, as the acme screw and acme nut must be custom matched sets. Thread grinding was used to create a highly efficient assembly with minimal backlash. Our engineers also created a custom acme thread design that met the requirements for the aircraft.
Once the design was finalized, prototypes were designed and manufactured for testing. This project is still in development, and the customer is performing tests to prove out their design. However, this design is flexible. If, once these tests are complete, if there are changes to be made, our engineers will work with the customer to move the project in the right direction.
Watch our video below about acme thread grinding
Acme Heat Treating
When high hardness or strength is required, acme heat treating may also be recommended. The key is to match the material, strength, and heat treat requirement to the application, as it does vary. Our PST engineers can help you decide on the best course of action for your application’s needs.
Which method is best for you?
Whether we decide to utilize thread rolling or thread grinding, choosing an acme threaded rod manufacturer that offers flexibility is key.
At PST, our ability to deliver quality custom projects is what sets us apart. You put it to the test, and if something needs to be adapted, we’ll make it work.
Are you looking for a partner to custom design an acme screw for your application? Our team of experts are ready to help. Contact us to get started.
