Is Independent G-Code Verification necessary? It is if you want to stay in business!
1) My CAM system already has machine simulation. What does VERICUT do that my CAM system doesn’t?
Unlike most CAM systems, VERICUT processes true G-code rather than internal CAD/CAM cutter location (CL) data. The same post-processed code loaded into your machine drives the VERICUT simulation. This becomes extremely valuable, especially when commanding working plane shifts, using multiple work offsets, working with subroutine calls, or validating rotary behaviors. These are just a few examples where CL data will not show the true picture.
VERICUT produces a feature-rich solid model called a Cut Stock used for collision checking and material removal, and its features can be directly interrogated for historical data related to associated tool paths.
2) How can VERICUT improve CNC programs?
VERICUT’s flexibility allows for custom control configuration to parse almost any G-code. This enables detailed syntax checking of program files and subroutines before simulation. Users can import a model of the finished part and have AUTO-DIFF automatically compare it to VERICUT’s Cut Stock model to clearly see any differences. The Cut Stock model’s accuracy can produce optimized code using VERICUT’s optimization modules. The high level of program validation allows users to eliminate prove-outs on the shop floor. By using VERICUT’s full capabilities, customers can ensure design intent, reduce cycle times, save on cutter costs, protect their machines, and feel confident in the entire process.
3) Can VERICUT simulate complex subroutines and branching logic?
Yes, VERICUT can initiate and update user and system variables just like the real machine. This allows VERICUT to properly navigate through complex branching logic and subroutines for virtually any control, including but not limited to Siemens, Fanuc, Okuma, OSP, and Heidenhain.
4) Can VERICUT simulate complex tool attachments, pallet changing, and head changing?
VERICUT allows for almost any type of attachment configuration including auxiliary rotary axis, angle heads, broaching tools, flash tooling, and bottle boring or facing heads that contain a secondary axis and allow for turn-milling operations. Spindle attachments can be loaded onto the machine using automatic M-code commands or through command comments in the NC program.
Part loading and pallet changing are supported using additional kinematics for the linear and rotary axes. Additive and hybrid manufacturing as well as composite fiber placement processes are also supported.
5) What kind of support can we expect from CGTech?
CGTech offers standard training classes for verification, machine/control building, and optimization. Customized training or services are also available and can be conducted virtually, on-site, or at a nearby authorized CGTech training facility. We can also come to your facility to review your process and identify how we can better help you do what you do best!
As hardware – especially processors and networks – becomes further commoditized, software becomes an ever-increasing percentage of system development and maintenance costs. A well-designed system that meets critical infrastructure needs can be used for decades but will require some maintenance as needs evolve and components reach ends of service life. Any of these challenges is difficult on its own; solving them all in a meaningful way is daunting.
Software represents the value that system developers provide. Because of the large investment in system software, protecting that investment throughout the entire life cycle becomes a critical part of managing cost and risk. Real-Time Innovations’ (RTI’s) Connext Data Distribution Service (DDS), in service for more than a decade, demonstrates the effectiveness of modular open systems architecture (MOSA) to protect system software investments.
Manage life cycle cost, risk
Cost and risk are not just part of the development or first deployment phase of a system, they remain throughout the project’s entire life. A project has no future if it fails by not completing immediate objectives. However, the outcome is not much better if the solution is obsolete by the time it is deployed or is not maintainable once it is fielded.
Considerations include upgrades to hardware components, operating systems, networks, and requirements to make improvements practical and affordable throughout time. For example, several RTI customers deployed systems using Connext DDS more than a decade ago and later required changes due to new requirements and replacement of obsolete equipment and operating systems. These were large implementations, so it was impractical to do a homogenous/one-time upgrade of the entire distributed system. The DDS communication infrastructure’s open-standard protocol, Real Time Publish Subscribe (RTPS), allowed RTI to commit to backwards-compatibility with support for numerous operating system and programming languages. Engineers were able to incrementally update functional system subsets throughout time without changing legacy components or subsystems. This allowed inexpensive incremental upgrades, avoiding the high costs of re-procuring an entire system.
This approach also protects investments in very expensive safety or security certified software solutions by ensuring continued operation with external, non-certified components which may update at a more aggressive pace, due to the lower cost of change. Users still needed some system- level tests before re-deployment, but sub-system and lower-level tests for the legacy components weren’t necessary.
Most systems deployed for decades needed to integrate with systems that had not been conceived of at design time. Consumer demand drove the creation of RTI Routing Service, a flexible tool that protects software investments by adhering to the modular, open system principles of open APIs and open wire protocols.
RTI Routing Service is a general-purpose, data-type aware, configurable, commandable, monitorable bridge for joining DDS-to-DDS communication domains or DDS-to-other communication data models and protocols. It leverages the ability of DDS to dynamically identify data types to provide a plug-in based architecture for the transformation, coalescing, and splitting of multiple data streams, greatly reducing application code and complexity when bridging to external entities. It also supports bridging and filtering between DDS Secure communication domains.
This design pattern only adds a single new member to existing systems, with independent processing and Quality of Service (QoS) for the external system side of the interfaces. Visualization and control of data routes and associated performance data are accessible using the RTI Administration Console, or alternatively, by subscribing directly to RTI Routing Service DDS data.
Shown, notional modular open system architecture deployment.
Reduce complexity
An open solution removes complexity from application business logic and encapsulates patterns as stereotypes, benefitting customers building products for such systems.
When details of reliable and secure communications or historical data retention are implemented and embedded in application software, business and infrastructure logic intermix, generating detrimental effects that are more dramatic in systems with long life cycles. Business logic becomes less valuable because it can only work with its own deeply embedded, custom communication logic, limiting its market for re-use. Custom communication logic also tends to become more complex due to tweaks that compensate for ordering network data or conforming to a specific network characteristic. Often poorly documented, these changes lead to code which users are hesitant to modify because knowledge of the original intent is lost.
A rich expression of QoS can be applied to various communication design patterns within the same application suite, separating business logic from communication to enhance the value for the business logic and improve productivity at integration by reusing proven, stereotyped communication patterns.
The open DDS Security Specification and its implementation into the Connext product suite shows the benefits of this separation. Users have added information security requirements to existing implementation, securing data in motion throughout all transports, including same-machine communications. In some cases, this was due to exposures proven by third parties. Using DDS for all internal and external communications allowed users to apply the security standard without changing application code. If communication security had been embedded in business logic for these mission-critical applications, closing the security gap would have been extraordinarily disruptive or cost-prohibitive.
Protecting software investment
There are no shortages of challenges when developing large, mission-critical systems, which makes adopting software development practices that protect the system throughout its life cycle essential for short- and long-term success.
The positive results from applying MOSA precepts demonstrate a path for protecting system software from changes which, while unpredictable, are inevitable throughout the life of a mission-critical system. Results show how adding external interfaces can be simplified and cost-effective, which minimizes system impacts. In addition, it proves that separating communication complexity from business logic facilitates system integration and maintenance.
About the author: Mark Swick, a systems architect at RTI, builds complex, distributed real-time systems. He can be reached at rti@karbocom.com or 408.990.7400.
Historical trend data can’t help MRO during unprecedented times
Features - MRO
Long-standing practices must be reevaluated using condition-based maintenance, digital twins, and evolved artificial intelligence to respond to COVID-19.
COVID-19 has affected maintenance, repair, and overhaul (MRO) facilities more heavily than most. With aircraft usage far below 2019 levels, most civilian MRO organizations have far less demand for their work. Reduced shop loads are further complicated by health and safety concerns. Additionally, MRO employees face personal complications including childcare. The pandemic has also weakened MRO supply chains – original equipment manufacturer (OEM) part suppliers and refurbishers are struggling.
All of this wreaks havoc on MRO analytics. Most MRO analytics solutions rely on long-term historical averages or typical data patterns. Nothing about the current market is average or typical. Work processes, productivity, part lead times, and demand are all exhibiting unprecedented behavior. Military MRO faces fewer changes in aircraft usage, but flying patterns have changed, and workforce impacts are much the same as in the civil market.
Aircraft health, maintenance
Aircraft fleets require frequent health monitoring such as inspections and logbook reviews to ensure readiness. Normally, aircraft fleet monitoring includes how well each aircraft is performing and how long it will be until major maintenance takes the aircraft offline. Maintenance intervention is required if an aircraft fleet doesn’t meet readiness goals.
Aircraft of the same make and model experience different conditions and usage. Variable usage introduces a level of uncertainty to plans and expectations for each aircraft and for the fleet because there are many factors to consider. This was difficult enough before the epidemic. Now it’s very, very difficult.
There are several ways to trigger MRO events on an aircraft – traditional methods (event-based maintenance, usage based, time based), and predictive or condition-based MRO. Although a wide range of options are available, most approaches and software to manage MRO are now ineffective.
Preventative maintenance is usually driven by use and time, forecasting maintenance needs based on past data and performance. A preventative system might follow a rule saying support personnel should perform a certain task after so many flight hours.
This practice sounds good in theory but can actually increase maintenance time and downtime even under normal circumstances. Now, some aircraft are in use, some are parked, and some are in storage.
While data inform MRO software, most solutions are deterministic. The analytics don’t consider variable differences, and ignoring uncertainty is usually bad. COVID-19 has added greater uncertainty. Even worse, historical data tell a different story about maintenance needs during different fleet usage, making the numbers less reliable.
Event-based maintenance is driven by unplanned, unscheduled events. This method is dependent on something breaking before it’s fixed. In theory, this saves time and resources because workers aren’t performing unnecessary maintenance tasks. However, some fixes aren’t quick or easy. Parts and skilled employees aren’t always available when needed. Event-based MRO is challenged by COVID-19 disruptions to the labor force and changes to parts supply chains.
MRO the right way
Condition-based maintenance is the most practical choice for organizations seeking to improve their MRO program. This method accounts for the number of takeoff/landing cycles, weather (in use and while parked), exposure to salt spray and humid environments, and many other factors. If analytics are used to estimate the condition and remaining life of critical components, the condition of each item can be targeted for the best fleet readiness and lower MRO costs. These analytics consider each system’s condition, not just flight hours, and maintenance isn’t dependent on damaging events.
Organizations are probably already gathering most of the data needed for condition-based maintenance. Some impressive results have been demonstrated without digitally transforming aircraft fleets. Even more impressive results are expected when predictive health analytics operate embedded in the aircraft.
Whether embedded or off-line, condition-based analytics use a digital twin of each asset. The best strategy goes beyond detecting decreases in performance. The digital twin predicts the remaining life before problems arise. Properly implemented, these twins account for spans of uncertainty. Real-world data is noisy and has random variation on top of the noise. Condition-based MRO solutions should reflect native stochastic processes.
Traditional methods are inherently limited, and during the epidemic these limitations have become important flaws.
Cloud-based twins naturally integrate with existing fleet data and can be deployed quickly. Edge-based alternatives operate with limited computation. Applications can successfully use either approach, therefore, a twin can run in the cloud or run reliably on limited edge computing devices. The light footprint means the digital twin can easily move as the aircraft fleet evolves, migrating from the cloud to the edge, or from the edge to the cloud.
Another emerging MRO development is evolved artificial intelligence (AI). Most aviation and industrial analytics require a choice between deterministic cause-effect simulations, or data-only AI. Cause-effect simulations provide transparency but are usually limited to engineering applications. Purely data-driven AI can be powerful, but is rarely explainable, and lacks predictive power and the precision of cause-effect simulations. Evolved AI blends cause-effect relationships, including physics and business rules, with data-driven methods, while incorporating realistic spans of uncertainty. This approach blends and focuses AI learning on topics where data defines a twin, but within the constraints of reality imposed on cause-effect relationships.
Summary
Using accurately informed analytics, operators can better manage maintenance and upgrade planning, optimize fleet use, improve schedules, prioritize supply chain, enhance flows, and shorten MRO cycle times. Predictive analytics – especially condition-based MRO – offer great promise for these difficult times.
Although the entire MRO industry has experienced a downturn due to current global events, the lull isn’t going to last forever. Once aircraft usage rises, organizations will need to be prepared for any necessary MRO actions because of the extended period of inactivity and daily wear. By using predictive analytics, fleet operators can ensure they avoid unnecessary, unplanned, or unscheduled downtime. Digital twins and advanced analytics reduce operating costs, a welcome result, now more than ever.
Performance comparison for common architectures (Source: IEBmedia)
Manufacturers using plasma, laser, and waterjet cutting machines are all looking for next-generation performance. New or upgraded machine purchases should provide capabilities that allow faster, more reliable production of higher-quality products. The reputation and success of a machine builder depends on demonstrating the best performance, design, and integration.
Optimizing the motion system improves all three. Five key opportunities for improvement include the fieldbus architecture, control loop bandwidth, servo motor design, feedback selection, and cabling.
Choose the right fieldbus architecture
Modern material forming systems almost universally employ some version of Ethernet for ease of use and performance. But within the Ethernet family, performance is relative, and choosing the wrong bus architecture can significantly reduce the execution speed, degrading cut quality and precision.
Whether using an industry-standard controller such as Hypertherm or a custom controller, the position points that define the cut are streamed from the controller to the drive deterministically. The time intervals between each X/Y set of points are strict and undeviating. Additionally, for highly dynamic applications such as precision cutting, these time intervals are very short – typically within the 500 microseconds to 1 millisecond range. Longer time intervals mean a less precise cut, while varying time intervals mean a distorted cut.
Ethernet connectors look the same, but various versions behave differently, so it’s essential to choose the right option (see Table 1, bottom left). Any drive’s fieldbus ports, however, must support a version of industrial Ethernet, and all devices on the bus must be compatible and correctly configured.
At Kollmorgen, we recommend EtherCAT for its fast, real-time performance as well as its support for CANopen, FailSafe over EtherCAT (FSoE), and other characteristics.
Optimize bandwidth
Higher bandwidth is intrinsically related to higher speed. Increasing control loop bandwidth stiffens motor behavior, decreases error, and improves transient response times. The result is more responsive control of position, velocity, and torque. For many everyday cutting applications, these factors may not be critical, but for next-generation cutting machines, control loop bandwidth is essential to performance.
However, while high bandwidth enables high performance, it also requires high-performing motion components. Higher frequencies might cause instability if the drive and motor aren’t able to take advantage of the rapid changes in the control loops. For example, a motor with high inertia may not achieve the required acceleration, and those limitations feed back into the control loops.
Another common issue is bandwidth-matching. A multi-axis application needs sufficient bandwidth to perform the required moves on each axis. But if the bandwidth doesn’t exactly match the different axes, the axes could respond at different rates to the control loop feedback, distorting the cut’s shape. While not directly related to bandwidth, applications incorporating a gantry also need cross-coupling between the axes on the two parallel sides to ensure coordinated motion.
Drives should provide simple, highly accurate tools for matching bandwidth across axes. When deciding on a servo motor, look for low-inertia designs to provide the acceleration and torque response needed in high-bandwidth, high-performance applications without creating disturbances in the system.
High-speed, high-precision CNC laser cutting machines can make cuts of virtually any size or shape in materials such as: carbon steel, stainless steel, copper, brass, and aluminum.
All photos courtesy Kollmorgen
Select, size motors appropriately
Another common mistake is undersizing a motor or selecting the wrong motor design without considering the risk of voltage or current saturation. A motor’s torque constant (Kt) can’t be higher than what the bus voltage will allow. If the drive can’t supply the necessary voltage or current, you may not be able to get the motor to perform required movements.
Incorporating electrical calculations up-front as part of the motor selection process prevents these problems. With a precise understanding of the available current and voltage, you can objectively evaluate the motor design and size needed.
High-speed fiber laser cutting machines can cut complex patterns into products such as metal tubes.
You may need to move to a bigger motor. Alternatively, you can consider the same motor with a different winding that balances voltage and current requirements. It’s highly probable you can get the performance needed without upsizing the motor or gain the ability to downsize.
Partners with motion engineering and product selection expertise can eliminate voltage and current saturation problems and ensure optimum performance given the realities of your electrical supply.
Match feedback devices to application requirements
Feedback devices provide information to the drive or controller to ensure that the motor or load reaches the required speed and position at the right time. Such devices can significantly influence cost, speed, and accuracy.
Incremental encoders provide two output signals indicating movement and direction, tracking only relative position, so users need digital interfaces to calculate absolute position. During a power interruption or application failure, the axis must be returned to a home position before restarting since the encoder doesn’t track absolute position. In some applications, this can be a safety issue. Incremental encoders are also somewhat susceptible to electrical noise interference and may require input filters and other measures to ameliorate the problem.
Absolute encoders generally cost more than incremental ones but provide several advantages. They generate digital codes representing the motor shaft angle, providing exact position and speed information without requiring further processing. If power is interrupted, an absolute encoder reports the correct position upon restart without needing to return to a home position. These encoders are also capable of very high resolution, provide excellent noise immunity, and are available in single-cable options.
Resolvers are another option. These analog devices are designed around an electrical transformer, using voltage comparisons between rotor and stator windings to provide absolute position throughout a turn of the motor shaft. Resolvers are rugged devices often specified for use in harsh environments, but typically don’t provide the resolution needed for high-precision cutting.
Frameless Kollmorgen KBM Series motors offer higher performance in a smaller space by reducing kinematics and increasing movement accuracy.
Each feedback type has its own use, but it’s essential to choose the most appropriate technology for the machine performance desired. Be aware that inexpensive feedback devices have hidden costs, such as difficulties in tuning motion to reliably meet requirements.
High-performance servo cables ensure the drive and motor operate at peak performance.
Choose cables for reliability, performance
It’s easy to overlook the importance of cables, but this isn’t an area to scrimp or treat as an afterthought. Undersized wire gauges in the cable will create problems with efficiency and reliability. If cables aren’t properly grounded and shielded, electrical noise can cause feedback errors and reduce system performance. Substandard insulation and connectors can cause failures throughout long-term use.
The cable number, size, weight, flexibility, and layout can also make a difference. In a gantry system, cables are part of the load, causing drag, weight, and compliance issues that the servo system must compensate for. A single-cable design may be useful because the cable and connector are easier to route and lighter than a two-cable system.
A gantry driven by a larger motor may benefit from the flexibility of two cables instead of a thick, stiff, single cable. As with all aspects of machine design, cable selection requires balancing properties without compromising quality.
Business success is often defined by companies that can first spot new technology, integrate that technology into the organization through the required hardware and training investments, and then use the new technology to differentiate from competitors. From the telegraph, to Ford’s assembly line, to establishing a dot-com presence, businesses with the budget and resources to invest in new technology before their competitors have reaped the benefits.
We’ve reached a tipping point where transformative technologies are coming to market far more frequently, each requiring a much lower investment. This means nimble startups with modest amounts of capital are suddenly comparably equipped to compete with deep-pocketed enterprises. Instead of having an advantage with world-class technology that startups simply can’t afford, established industry leaders are forced to prioritize agility and speed-to-market more than ever before.
The cloud, the storm
The biggest equalizer is the cloud. All industries can see beyond using the cloud to host business tools and are now embracing its power to drive true business transformation. Research and advisory firm Gartner notes the fastest-growing segment of the market is public cloud system infrastructure services, a segment that experienced huge growth in 2019. And, by 2022, 90% of organizations that use cloud infrastructure services will demand platform-as-as-service capabilities from their provider. Driving this increasing appetite for cloud-based platform capabilities is a growing desire to execute digital transformation projects. If the predictions are correct, every aspect of product design and manufacturing is about to undergo a dramatic shift.
While all industries are ripe for cloud- fueled startup disruption, the aviation sector stands out thanks to a few compelling factors brewing to create a perfect storm. Technological breakthroughs in aircraft and propulsion designs have produced prototypes that are exciting, but never seen as commercially practical before the era of digital transformation. And, established aviation leaders are reeling from the global pandemic crippling the travel sector. As the aviation industry re-aligns in the coming years based on new consumer travel demands, industry disruptors may be able to bring their products to market.
David vs. Goliath
Without requiring expensive upfront infrastructure investments, startups and small- and medium-sized businesses can quickly embrace transformative technologies previously available only to the largest competitors, scaling up as needed. This is significant for highly regulated industries with large barriers to entry – such as aviation – where startups have been effectively walled-off for decades. It’s not enough to build a disruptive product, but it must be documented, manufactured, and inspected in ways that are anathema to small organizations.
Now, companies such as Vertical Aerospace and Boom Supersonic can access tools to fulfill stringent regulatory requirements so they can focus on their core business of creating game-changing aircraft. Boom Supersonic is bringing faster-than-sound air travel back to commercial aircraft, using powerful cloud-based design and simulation tools to overcome challenges that 1960s-era design technology could not. Vertical Aerospace is on the verge of launching a winged eVTOL that is significantly quieter than a helicopter, allowing it to travel more freely over areas where noise regulations can restrict aircraft access. Technical challenges such as weight reduction and aerodynamic simulation are offered by world-class design tools available via the cloud in ways that weren’t possible even 10 years ago.
Fast mover advantage
Cloud-based product innovation platforms foster agility and collaboration in small and large organizations. The talent needed to create the next breakthrough product probably isn’t located in the same city as your physical headquarters, and new design concepts and technologies require new ways of collaborating with colleagues. File-based approaches, such as sending email attachments or uploading the latest version of a document to a server, don’t allow a business to move quickly enough.
With a single, central repository of data that gets updated in real-time, teams can collaborate more effectively and boost time to market, or make a quick pivot when circumstances require a new approach. For businesses that rely on a global supply chain, a cloud-based business platform allows internal team members and external stakeholders to have a single source of information. When the product development team makes a change, it’s immediately cascaded throughout the worldwide organization, from the design team, to the manufacturing team, to the packaging team, and to all the external suppliers and distributors.
Another electric aviation pioneer, Eviation Aircraft, selected Dassault Systèmes’ cloud-based innovation platform for its design and simulation solutions and for the inherent collaboration benefits of a cloud-based business. With a global supply chain involving hundreds of sub-contractors, Eviation can streamline its product development process by having its stakeholders working from the same dataset.
The transformative benefits of the cloud are clearly a game-changer to startups, but a company of any size beginning its digital transformation should closely examine the benefits. Define company goals before starting the journey and look at the tools industry leaders are using. The best way to ensure the success of such a massive undertaking is to embrace technology that breaks down information silos, allows teams to leverage talent from anywhere in the world, and converts your supply chain into a value network. Combining the power of a product innovation platform and the cloud is the key to success.
