Digital Thread refers to the stream that comprises of a digitally connected system involving conceptualisation, design, planning, manufacturing/production, maintenance and feedback of tools & processes. Typically, these are various software and hardware modules that are connected across a common platform; however, with the advent of cloud-based technologies, the digital thread is expected to be more platform independent than ever. In simple terms, it is a well-integrated process of envisioning, designing, making and analysing products and services.
OEMs are currently under great pressure to innovate, produce and manage their programmes, while keeping costs low and quality and customer satisfaction high. A digital thread will enable them to build a process that will provide a seamless experience to employees, suppliers and customers alike. In order to understand better about the advantages that the digital thread offers, it is important to look at each stage of the macro process.
Traditionally, there has been no set standard in the conceptualisation stage. Concepts and ideas have been depicted by hand sketches, flow diagrams, clay models, paper crafts and many other methods. However, in the digital thread, all of these and many other methods, can be visualised in a common interface. Most tools allow for hand sketches to be imported into the conceptualisation stage and use digital tools to refine or digitise these hand sketches to lay the foundation for the design stage.
Similarly, ideas from alternative methods can now be easily digitised using various hardware/software combinations. New age advancements in computer hardware has also enabled the use of styli and haptic devices to input concepts directly into the digital thread by means of real-time sketching, sculpting and brushing. Through an online collaborative platform, feedback and approvals can be sought from internal and external stakeholders at every critical step.
Design, simulation & prototyping
Digitised concepts from the previous stage become building blocks or the foundation of the design process. Curves and other mathematical information created in the concept stage, in a digital thread, allow designers to use the information to build upon or assist in feature creation of a CAD model. In a digital thread, both stages use a common file format to avoid confusion as well as allow for a tighter integration between the two stages. Using this common file format, designers are able to save considerable amount of time in building up the first CAD model and use simulation and validation tools embedded in the software to validate the design. Like before, online collaboration between various stakeholders allow design changes, corrections and simulation to ensure that the design is accurate. If needed, a physical prototype can be produced quickly using many modern methods such as 3D printing so as to enable customers to have a ‘look & feel’ of the product.
The CAD domain essentially involves a large part of what used to be ‘Design Planning & Validation’ and a large bit of modelling. There is a great demand for direct modelling and also a paradigm shift from the traditional ‘Parametric/ Constraint based modelling’ to the former. Interestingly, most CAD work that goes on in the manufacturing industry relates to design adaptation and design to manufacture, thereby, increasing the demand for CAD platforms that can work with either solids or surfaces and have a large focus on providing the user with tools to adapt designs for manufacturing by ‘prepping’ them with various DFM tools. In addition to this, tooling and electrode design continue to be the major demand factors in the complex modelling/ design domain.
Carrying on from the previous stage, various tools in the digital thread are now able to quickly setup processes and templates that will allow the designed components to be physically produced using one or more methods. CAD models, for example, become the input information for both additive as well as subtractive manufacturing and the digital thread provides NC output to relevant machines to physically produce the final components.
On the CAM front, there is always a demand to finish the toolpath computations at faster times, while maintaining or increasing reliability. Since machine tool, CNC controls and cutting tool technologies are evolving at a rapid rate, CAM software are also required to keep abreast with these developments. Demands on post processors for complex machine kinematics continue to challenge the depths of this technology.
Dynamic Motion toolpaths
In order to machine components efficiently, a sophisticated set of rules that take into consideration a broad data set are required. In order to create the most efficient cutting motion possible, special toolpaths such as Dynamic Motion toolpaths calculate more than just the areas where metal will be removed; they also take into account the changing condition of the material throughout various stages of machining. Such toolpath has enough intelligence to look ahead, see what’s coming and modify feeds, speeds, stepovers and cutting motions based on everchanging material conditions. Significant benefits include radically shorter cycle times, less wear and breakage of tools, and less wear on machines.
By dramatically reducing stepovers and air cutting, these special toolpaths can reduce cycle times by 25 to 75 per cent. Dynamic Motion toolpaths ensure that the tool spends most of its time cutting at full-depth with far fewer stepdowns resulting in more parts cut in less time. These toolpath strategies use the full flute length so users will get even wear and heat distribution resulting in fewer tool changes and less grinding that slows down and costs money. Dynamic Motion produces consistent chip load, reducing vibration and extending the life of machines. The looping motion eliminates abrupt directional changes, keeping machines more accurate with less maintenance.
Roughing hard materials can also pose a challenge but Dynamic Motion toolpaths make it easier by ensuring even heat and load distribution throughout the cut. This even distribution prevents material surface hardening and reduces the risks of tool breakage, giving more consistent, predictable results.
Assembly plans and auxiliary processes can also be scheduled in parallel to reduce lead times and ensure just-intime manufacturing. The digital process is also able to monitor the productivity as well as down-time of each machine to help decision makers in taking timely actions. Finally, a completely connected system or a closed loop system, so to say, will also help in monitoring product behaviour during its lifetime, thereby, providing invaluable inputs to the design stage. ☐