Linear Ramping Down in Milling

April 5, 2018

Definition of Linear Ramping Down: It is a movement performed by the milling cutter, using the axial Axis (Z-Axis) simultaneously with other axes like X-Axis, Y-axis or X+Y Axes. It is used to perform Pockets, Cavities or Slots operations succesfully, eliminating the need for a drill.

Normal Shoulder Milling

 

During a typical Shoulder Milling Operation, the main cutting forces are received by only one area in the insert edge.

Normal High Feed Milling

 

The High Feed Milling Operation also remains with only 1 main area of contact, as it can be seen below.

 

Contact Area

 

During a Linear Ramping Down Milling Operation, there are additional parts of the insert edges receiving cutting forces. This additional stress, increases the Radial Forces and may create long chips.

 

 

Cutting Edge in Contact

 

As it can be seen on the picture below, the operation is performed by 3 different areas of insert :

1) Periphery cutting with the front insert

2) Bottom cutting with the front insert

3) Bottom cutting with the back insert

Feed Rate

 

There is a recommendation, regarding feed rate, to achieve good results and avoid insert breakage or milling cutter bodies damages:

 

Reduced feed rate => 50% - 75% of normal feed

 

Depends on the material, hardness, clamping rigidity and machine conditions.

When performing a slot milling directly after ramping, is strongly recommended to keep the same reduction for a distance equal the milling cutter diameter.

After moving this distance, the feed rate can be adjust for 100% of normal feed rate.

Avoid Chips

 

Always when possible, use air blow to keep the machining area free of chips.

 

Deep Slots Recommendation

 

When performing deep slots with several passes, the productivity level can be increased by using Continuous Ramping in both directions, instead of using single passes (ramping in only one direction). However, it is very important to lift the milling cutter in a distance “h”, before changing the cutting direction to prevent damage to the central part of the cutter body.

 

Deep Slots – Lift Height Calculation

 

 

Insert Width – Cutter Families

List of Lamina´s Milling Cutters, inserts and respective Insert Widths.

 

Most suitable inserts for Linear Ramping Down Milling

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Maximum Ramping Down Angle

 

The maximum ramping down angle is informed in our catalogue, like shown below.

Always respect this value in order to perform a safe operation.

 

 

 

 

 

 

 

 

 

 

 

When AVOID Linear Ramping Down

 

 The Ramping Down Operation, must be applied only in cases the Pocket, Cavity, Slot dimensions are close to the milling cutter available.

In cases when it is possible to perform a Circular Ramping Down, we strongly advise to use this strategy to do the job. The chip control will be better and the process security level will be higher.

 

 

Summary

 

Linear Ramping Down Milling is a milling strategy to open slots, pockets and cavities, where the dimension of the slot and the milling cutter are close to each other. It can be performed with high level of performance in terms of productivity and process security, without using drilling bodies. Following the recommendations in this tip, you can increase the machine utilization, while decreasing the need for additional tools.

 

 

 

 

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