successfully added to cart
View Cart

Choosing Between Periphery Ground and Molded Inserts

in Indexable Milling Tools for CNC & 5-Axis Machining

Many metal cutting professionals may not realize that the way an indexable milling insert is manufactured has an impact on tool life and surface finish. Let’s start with the basics. There are two basic ways to ensure the size and edge prep of an indexable milling insert: A) either the insert is “pressed and sintered to size (PSTS),” meaning that the finish size and edge prep is engineered into the press molds and heating calculations, so that the insert meets the tolerance requirements, or B)  the insert is “periphery ground to size (PG),” meaning a secondary grinding process is used to bring the insert to the final size. Regular industry standard is following the “M” tolerance for PSTS inserts which allows for greater tolerance variation on the diameter. WIDIA global standard is set up to a tighter tolerance “P” for high precision PSTS inserts to achieve a better axial runout and positive impact in better tool life and surface floor finish.

PG inserts are the first choice for finishing, high precision applications like die and mold. In addition, due to sharper edges, PG inserts are well-suited for machining of non-ferrous materials, like aluminum and brass.

Whereas, PSTS inserts are the first choice for semi-roughing and roughing applications. Inserts with tolerance class G, K, C, H are PG. Those with tolerance class P are PSTS.

The MS geometry insert for the TDMX modular drill platform provides increased stability when drilling stainless steels and super alloys.
The MS geometry insert for the TDMX modular drill platform provides increased stability when drilling stainless steels and super alloys.
The MS geometry insert for the TDMX modular drill platform provides increased stability when drilling stainless steels and super alloys.

The M class tolerance is much more wide open when it comes to the IC and the “M” dimension (distance from IC to the wiper flat). The P tolerance is a balanced, +/- 0,038 (.0015), for more consistent size.

To get the best surface possible, be sure to align the topography letters on the insert the same way each time. i.e. MM should start in the same position in each pocket and roll inward with each index.

If you create a new solution, you will lose any solutions you were working on already. How would you like to proceed?
You are about to create a duplicate . Do you want to proceed?
You are about to delete Do you want to proceed?
What would you like to rename your to?
Please enter a valid name
Please enter a name for the duplicate
Please enter a valid name
You are about to add to your My Solutions page. Do you want to proceed?
Please enter a valid name
Send a copy of

Please enter a valid Email
Please enter a valid name

We have found the following CAD Drawings

Select the files you are looking for and download them all at once

You should be logged to see your dashboard information
The product/s () you were trying to add to the cart is/are not available, please contact customer service.
item(s) successfully added to the cart
View Cart