Standards Development

Scope

This document specifies the dimensions of tapered polygonal receivers with flat contact surface (PTI). These shanks are the female part of the interface to the (in cutting process non-rotating) tool carrier of machine tools (e. g. turret lathes, turning centres).

The draft specifies four types of machine-side interface types, which differ at the face contact.

The bores for receiving the tool shanks themselves are designed identically for all types. Receiver type F has one hole for the coolant supply (F = fluid); PTI-F type tool holder can be installed in 0°- and 180°-position.

Receiver type H has a primary coolant hole for the main supply and a secondary coolant hole for an intermediate tool position on the face contact (H = half). For PTI type H holders an installation position offset by 180° is not possible. Receiver type A has one hole on the face contact for the primary coolant supply and one additional hole for supplying the tool holder (driven tool) with sealing air (A = air).

Two more bores allow the installation of PTI-A holders with spring-type straight pin in 0°- and 180°-position.

Receiver type X has a primary coolant hole for the main supply and a secondary coolant hole for an intermediate tool position on the face contact.

Additionally the type X receiver has one hole for supplying the tool holder (driven tool) with sealing air and two bores for the 0°- and 180°-position of the spring-type straight pin of PTI-A holders.

Purpose

The proposed standard deals with the topic "Interface between turret disk and tool holder" in lathes and turning centers. It is divided into three parts and describes the interface elements "shank" (part 1), "receiver" (part 2) and "coupling" (part 3). Initially, three sizes are specified in the proposed standard. The desire for standardization of the different turret interfaces has been growing for decades among experts and especially on the consumer side, but there has always been a demand to further increase the performance (accuracy, stiffness, torque transmission) of the interfaces. Both goals were achieved with the PTI development. For the first time, the new PTI interface was installed in a radial turret on a lathe and successfully tested with stationary and driven tools under chip removal. The most powerful interface solution is available, which can be used as a standardized version by numerous providers. It offers the end user the advantage of bringing uniformity to the process flow, which is also absolutely necessary in the area of mechanical interfaces for today's 4.0 production. Machine manufacturers can use the new interface to increase the performance of the entire machine or create more space with smaller interface sizes and increase the range of functions of the machine and thus increase productivity.

For both stationary and driven tools, the interface was designed in a way that an optimal media supply with coolant and air is possible. In addition, the transmission of data and electrical energy became more important. A second important topic was the investigation of the interface with regard to the suitability for different turret designs (radial turret, axial turret,...). All conceptual work and investigations ultimately resulted in the design of a standardized interface.

PTI is a taper / face contact system that can be clamped with a quick-change clamping mechanism acting on a clamping shoulder on the shaft. While shank and receiver are completely described in the standard proposal, the clamping system itself is not part of the standardization. In addition, as with comparable systems (BMT), the tool holder can also be attached with four screws. The design of the drive coupling for the driven tools is specified in a separate standard section. The turret-side drive, like the clamping system, is also not part of this standard. With the specification of coupling dimensions for driven tools, the standard proposal is completed and the requirement for universal uniformity of the tool holder is also taken into account in the rotating area. 

The market spread of comparable VDI systems was decisive for determining the sizes of the PTI. The most common system VDI40 finds its counterpart with the PTI65. The two smaller sizes VDI30 and VDI25 correspond to PTI54 and PT42. The need to design larger and smaller nominal sizes will be determined in the further standardization process.