Rough Machining

Rough machining is an integral part of the on-site services offered by Test Devices by SCHENCK, enabling us to provide shorter turnaround times and greater overall production efficiency. Clients can also create highly specified products via rough machining, allowing us to tailor products to unique requirements as quickly and smoothly as possible.

Leading jet engine OEMs rely on forging pre-spinning services provided by Test Devices by SCHENCK as an essential step in the manufacturing process for creating disks for state-of-the-art high-performance engines.

The forging pre-spin process is a highly specialized operation that requires flawless performance. The experts at Test Devices by SCHENCK are properly trained and experienced in:

• Choosing the proper spin tooling design for complex geometry parts and repeated use
• Commissioning and performing pilot runs
• Confirming and monitoring accurate levels of disk growth
• Troubleshooting issues related to rotor dynamics
• Optimizing and troubleshooting quality process–related issues

How Rough Machining Fits Into the Pre-Spin Machining Process

Parts that require spin testing, such as jet engine disks, begin as rough forgings that must undergo machining to achieve tighter tolerances and further prepare the part for spin testing.

Step 1: Pre-Spin Machining

The first step in preparing a component (such as jet engine discs) for spin testing involves performing rough machining, or pre-spin machining. The goal of this stage is to create the features required to attach spin tooling. The tolerance for this step are typically in the range of +/- 0.005 in. (0.127 mm).

This is not as tight as the tolerances required for finish machining, which are typically +/- 0.001 in. (0.025 mm). However, it is a significantly tighter tolerance than what forgings feature, which is +/-0.020 or 0.508 mm. Pre-spin machining processes leave approximately 0.050 in. (1.27 mm) of material on all touched surfaces.

Step 2: Pre-Spin Testing

After pre-spin machining has been performed, the component is ready to undergo pre-spin testing. During this process, forged components are spun to a specific speed to yield the material, reduce residual stress imparted during the forging process and homogenize the forging stress state overall. This leads to improved manufacturing efficiency, lower production costs, and enhanced overall performance.

Step 3: Rough Machining

Also referred to as semi-finishing, rough machining helps to achieve more precise tolerances and is the final task our team performs before sending the parts back to the customer for finish machining. The goal of rough machining is to remove more material that was determined to be excess during the pre-spin testing.

Rough machining has a tolerance of +/- 0.005 in. (0.127 mm) and leaves approximately 0.050 in. (1.27 mm) of material on all finish dimensions. This process is a critical step in the overall manufacturing process.

Rough Machining Services at Test Devices by SCHENCK

Test Devices by SCHENCK is highly experienced in transforming components, through pre-spin and rough machining processes, taking rough forgings all the way to the state ready for final machining. Among our list of services provided are:

• High-nickel content aerospace superalloy machining
• Precision machining of critical rotating components
• Producing machined features within the tolerance of ±0.0005”
• Creation of high-precision geometric shapes from rough forgings
• Inspecting critical rotating parts with coordinate measuring machines (CMM)

We rigorously document all our manufacturing processes to ensure the precise execution of every stage. We provide a wide range of on-site engineering support services, and we possess the advanced analytical and design expertise needed to manufacture critical rotating parts. To reduce lead times as much as possible, our services incorporate all elements of the manufacturing process, including:

• Machining
• Spinning
• Inspection
• Balancing

Benefits of Rough Machining

Our rough machining services come with many benefits. Because we combine the machining, spinning, inspection, and balancing processes into one package and provide these services in-house, we’re able to reduce the overall cost and production time of the components we produce. This quicker turnaround also allows for an increased speed-to-market production, which provides our customers with a competitive edge.

Additionally, shorter supply chain lead times resulting from consolidating multiple manufacturing steps from one supplier can result in the reduction of WIP levels (ex. 10 pc/week and 8 weeks lead time = 80 pc/WIP, 6 weeks lead time = 60 pc/WIP). Test Devices by SCHENCK has expert staff supporting each step of the process, ready to respond to uncertainties and troubleshoot any problems in an expeditious manner.

Learn More About Our Pre-Spin Machining Process

Test Devices by SCHENCK offers industry-leading services that transform the reliability of rotating parts. Our rough machining services have been designed to save you time while adhering to rigorous quality requirements. We are ISO 9001:2015 and AS9100D certified and are equipped to handle everything your project needs to succeed, from product design to spin testing and failure analysis. To learn more about our rough machining services, contact us or request a quote today.

Rough Machining FAQs

Rough machining is an essential aspect of preparing rotating components, like jet engine disks, for spin testing. If you’d like to learn more about how this process works and what makes it different from other types of machining, browse our most commonly asked questions below.