Page 49 - Kaleidoscope Academic Conference Proceedings 2020

A CASE STUDY FOR MODELING MACHINE TOOL SYSTEMS
USING STANDARD REPRESENTATIONS

2
1
1
Maja Bärring ; Guodong Shao ; Moneer Helu ; Björn Johansson
2
1 Chalmers University of Technology, Industrial and Materials Science, Hörsalsvägen 7A, Gothenburg, 41296, Sweden
2 National Institute of Standards and Technology (NIST), 100 Bureau Dr., Gaithersburg, MD 20899, USA

units, as well as the kinematic relationships between the
ABSTRACT mechanical units of the machine. The kinematics model of
a machine tool defines the motion constraints for machine
components that are related to each other [8]. For example, a
Machine models play an important role to support decision five-axis machine is generally defined by two rotational axes
making for purchasing, scheduling, and routing in to rotate and tilt either the tool or the workpiece and three
manufacturing. However, it is challenging to share a orthogonal linear axes x, y, and z. The machining functional
machine model that is developed using proprietary formats. properties, i.e., mechanical and kinematical properties in the
A model of a fully assembled machining system in a neutral machine model, will define and constrain the movements and
format can help overcome this challenge. Standard-based speeds of axes [7]. Simulation of kinematics helps identify
machine tool models will not only facilitate information manufacturing issues at an early stage and correct them
reuse but also enable model exchange between systems. In before production. Those issues could be errors in the tool
this paper a case study is discussed to demonstrate the initial path, collisions between machine components and machined
effort of a standard representation for a machining system parts, and poor quality of the final product. Simulation is the
including both component geometric and kinematics safest and most cost-effective way for verification of a multi-
information. This standard-based machine model will be axis program, and it supports the concept of virtual
easily imported to another tool. machining [6] [9].
Keywords –CAx tools, kinematics, Computer-aided (CAx) tools normally provide a virtual
interoperability, machine model, standards, smart environment that enables the simulation of machining
manufacturing systems, STEP processes with a realistic representation of the kinematics,
static, and dynamic behavior of the real machine tool [6]. The
1. INTRODUCTION x in CAx is an abbreviation for the family of computer-aided
tools that are used to create virtual environments, for
Smart manufacturing systems (SMS) are fully integrated, example, Computer Aided Design (CAD), Computer Aided
collaborative manufacturing systems that will respond in real Manufacturing (CAM), or Computer Aided Engineering
time to meet changing demands and conditions in factories, (CAE). A variety of commercial CAx tools from different
in their supply network, and in customer needs [1] [2] [3] [4]. vendors are available and have been used by manufacturers
SMS requires the digitalization and integration of to represent their products and resources to support design,
components of a manufacturing enterprise including operation, and maintenance activities. These activities
manufacturing resources such as computer numerical control involve process planning, tool path verification, cost
(CNC) machining systems [5]. estimation, process simulation, and CNC programming [6]
[7].
A CNC machining system is a fundamental element in
production systems and typically consists of a machine tool, With the multiple CAx tools provided by different vendors
cutting tools, auxiliary devices, material-handling devices, serving the same purpose, barriers for sharing and
and fixtures. A CNC machine model is a conceptual exchanging machine models with kinematic and geometric
representation of the machine tool and has a logical information between different systems exist [10]. Because
framework that enables the representation of the machine’s each vendor has its own CAx environment, which is non-
functionalities. The information built into a machine model homogenous, users are stuck with the specific format of the
can be used throughout the life cycle of a machining system CAx software they use. Redundant efforts have to be made
and by various users in the decision-making processes. for recreating the same machine model using different CAx
Examples of model use include manufacturing capability tools within a company; machine models with complex
evaluation, process validation, and production planning [6] kinematics may be difficult or very time-consuming to
[7]. It consists of modules for describing the configuration of remodel or convert. In addition, all these issues also make it
the overall structure, geometric shapes of the mechanical difficult to efficiently define and analyze manufacturing
capabilities for production planning and equipment

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