Mitsubishi Heavy Industries Technical Review Vol. 57 No. 3 (September 2020)
1Ultra-thin Linear MPFA Scale for Industrial Machinery

Mitsubishi Heavy Industries Machine
To o l C o . , L t d .
TEL +81-75-861-3313

In recent years, there has been increasing demand for higher-speed and higher-precisioncontrol of linear drive mechanisms in various fields, including industrial handling systems, mobilerobots, semiconductor/liquid crystal manufacturing systems, and food processing equipment. With
such a background, an increasing number of devices have adopted linear motors and precision
position detectors instead of conventional servo motors and ball screws.
Mitsubishi Heavy Industries Machine Tool Co., Ltd. has marketed the MP (MitsubishiPrecision) scale, which is a high-speed and high-precision scale that is resistant to harshenvironments, mainly for use in machine tools. This time, we have developed the optimal scale forlinear motor position detection that can be used by a wider range of customers. This reportpresents the ultra-thin linear MPFA (Mitsubishi Precision Factory Automation) scale for industrial
machinery, which is an achievement of the development.

|1. Features of ultra-thin linear scale MPFA
The MPFA scale has various new excellent features, while also inheriting the features of theMP scale marketed for machine tools. The scale component of the MPFA scale has a thickness of
0.4 mm as a tape-type scale, which was reduced from the roughly 10 mm of the MP scale by using
a stainless-steel strip as the new base material.
(1) Thin and compact
The MPFA scale has the scale dimensions of 13 mm in depth and 0.4 mm in height, andthe head dimensions of 50 mm in width, 21 mm in depth and 12 mm in height. Due to thiscompactness, a thin scale that fits inside a linear motor stage where the mounting space islimited has been achieved (Figure 1).
In spite of its compactness, the MPFA scale has the same high-speed and high-resolution
performance as existing products (response speed of 30 m/s and resolution of 0.1 μm).

Figure 1(2)MPFA scale mounting dimensions

Figure 2 Example of application tomultiple-head mechanism

Utilization in various applications
The tape-type MPFA scale can be cut to any length, so a scale with a length suitable forthe application, from a long size to a short size, can be made. In addition, multiple-headdetection, which allows the use of multiple heads on a single scale, is possible, so it can be used
for applications where many products are simultaneously handled, such as food processing
equipment (Figure 2).

Mitsubishi Heavy Industries Technical Review Vol. 57 No. 3 (September 2020)2(3)High cost performance
A new manufacturing method that applies the latest printing technology is adopted. TheMPFA scale realizes low-price production by pursuing cost reduction in manufacturing.
(4) Easy adjustment
The MPFA scale comes standard with the "MP VIEW" monitoring function, which candisplay the gap between the scale and the head and the current position numerically just byconnecting it to a PC. This makes for easy adjustment during assembly and maintenance(Figure 3). In addition, the user can acquire scale information (position information, detailed
data on abnormalities, etc.) with a computer, etc., using disclosed protocols.

Figure 3(5)

MP VIEW (connection to PC)

Excellent environmental resistance and stable accuracy
Detectors for machine tools must be able to be used in environments where chips and oil
are scattered. The MPFA scale uses the same electromagnetic induction method as the MPscale, which has been proven for use in machine tools, so it is a highly-accurate detector that isdurable in environments where dust, oil, condensation, etc., exist.
In addition, since there is no deterioration in accuracy due to aging thanks to the completely
non-contact structure, accurate position detection can be maintained over the long term.

|2. Specifications
Table 1 shows the specifications of the MPFA scale, and Figure 4 shows an example ofmounting to a linear motor stage.
Table 1 Specifications of MPFA scale
Item

Description

Structure

MPFA-HI (head)
MPFA-TI (scale)
Incremental
Up to 9950 mm(Scale length－50 mm)
Open type

WiringOne wire on head side

Scale dimensions

13 mm (D)×0.4 mm (H)Model type
Type
Effective stroke

Head dimensions

50 mm (W)×21 mm (D)×12 mm (H)Resolution

1.0 μm, 0.1 μm

Multiple-head mechanism

configurability

Response speed

30 m/sCompatible individually with products from servo amplifier manufacturers
A/B/Z phase rectangular pulse open interface

InterfaceMitsubishi Heavy Industries Technical Review Vol. 57 No. 3 (September 2020)
3Figure 4

Example of mounting|3. Future prospects
We will continue to work on product improvements such as support for absolute detection
and the expansion of interface compatibility with products from various servo amplifier
manufacturers in order to provide a wider range of customers with solutions to the problems theyare facing.