A member of the American group ITW (Illinois Tool Works), Spit Paslode is located in Valence in the Drôme department in France. The tools design office designs power tools (drills) and nailers (driven by gas, compressed air or powder). The gas-driven nails are the brand’s flagship product.
Founded in 1951, Spit Paslode is two brands: Spit for concrete and steel and Paslode for wood applications. Spit Paslode manufactures and markets comprehensive ranges of fixing systems tailored to all construction applications – nailing and stapling, resins, mechanical fixings and power tool assemblies.
Gas-driven nails are Spit Paslode’s signature product. They work as follows: A piston is powered to speeds of about 40 meters per second (m/s) by a fuel combustion, pushing the nail in the support (wood, concrete or steel).
As a result of its high-power density, gas technology is the only option capable of producing lightweight, portable and cordless tools. Cordless technology makes these tools easy to handle for builders who use them on difficult platforms (roofs, scaffolding, ceilings) on a daily basis. The tools comprise up to 200 different parts and are fitted with an electronic injection system, which allows them to be used over a wide temperature range (-15 degrees Celsius to 49 degrees Celsius).
“To maintain a competitive edge, especially when faced with the emergence of electric nailers in the low-power ranges, our design office is constantly working on reducing the weight and bulk of the tools,” says Olivier Baudrand, research and development (R&D) engineer at Spit Paslode.
“The very violent, repeated shocks push the mechanics and onboard electronics to the limit, which often leads us to strengthen the parts. Finalizing the development is difficult since it is only through endurance test that we can identify certain failures and breakages caused by fatigue. Weight reduction is also a real challenge.” For the development of a new wood nailer that uses a more complex, innovative combustion technology, the R&D team found itself facing a technical challenge: accurately understanding the physical phenomena at play in the system to improve stability and system performance.
“The traditional, empirical method based on trial and error is long and costly in terms of prototypes,” says Baudrand. “Worse, it does not lend itself to a rapid, detailed analysis of the physical phenomena. The results are sometimes difficult to analyze, as different parameters vary simultaneously. For this new project, we needed to quickly explore a large number of configurations, all within ever-tighter time frames. That’s why we decided to adopt a digitalized method.”
Spit Paslode first tried to use spread sheet software, but that quickly showed its limits: long calculation times, modifications that were difficult to implement, insufficient modularity and lack of convergence of certain calculations. In search of a suitable system modeling and simulation tool, Spit Paslode decided to use product lifecycle management (PLM) specialist Siemens Digital Industries Software’s Simcenter Amesim™ software, part of the Simcenter™ portfolio, the integrated simulation platform for multidomain mechatronic systems simulation.
“The 01/1D simulation makes it possible to analyze the dynamics of complex, multidomain systems like our gas nailers,” says Baudrand. “It underpins the development, from the preliminary specification phases to the subsystem validation testing.”
Spit Paslode’s decision was prompted by the ease-of-use, openness and extensive libraries of predefined and approved components of Simcenter Amesim. The software tool is suited to modeling a number of multi-domain systems, including: mechanical, fluid, thermal, thermohydraulic, thermopneumatic, electrical, electromechanical and signal processing.
The R&D team mainly used the pneumatic and gas mixture library for this project. The combustion chamber was developed internally to meet the specific needs of the project. With Simcenter Amesim, users can develop their own component models by assembling different standard submodels or by directly programming with the submodel editor tool in Simcenter Amesim.
The Spit Paslode R&D department worked in close collaboration with BSIM Engineering, a Siemens Digital Industries Software partner, to adapt and get familiar with Simcenter Amesim. “BSIM Engineering has been fast and accurate in answering my questions,” says Baudrand. “I am very pleased with their contribution.”
The 0D/1D model developed for this project comprises more than 100 global parameters, including geometry, volumes, air sections, masses, pressures, forces, thermal exchanges, fuel and combustion. The variation of the sizing parameters was analyzed using simulations in batch mode. The results analysis, performed via graphs and curves, enabled users to better understand the overall operation and identify the critical parameters, then determine the necessary design changes.
“In this case, the project already advanced considerably,” says Baudrand. “There was little room for maneuvering to modify the actual design of the tool. Thanks to the parameter variations, we realized that a change to the exhaust port section could resolve the critical problem with which we were confronted. This modification was in no way intuitive since it had an indirect impact on the malfunction. A quick validation by prototyping allowed us to check the prediction’s plausibility. As a result, our level of trust in the capacity of simulation tools increased significantly.”
Throughout the analysis phase the R&D team worked with the computer-aided design (CAD) office. Together, the teams analyzed the impact of system parameter changes on the design. Iterations were carried out, as it was not always possible to change certain geometric characteristics of the product, especially during the downstream verification phase. The graphic aspect (the diagrams and curves) was a key communication element between the teams.
Spit Paslode found that its Simcenter Amesim users immediately appreciated the breadth of its component libraries, the precise results and user-friendly interface.
“In the space of just a few weeks, we have performed hundreds of simulations,” says Baudrand. “We have accurately analyzed the influence of the parameters and understood the modifications that needed to be made to our product in order to optimize its operation. Without Simcenter Amesim, all of this would have been extremely long and costly, if not impossible.”
Extending the use of Simcenter Amesim covers the entire system engineering V-model, from the concept and system architecture to the tests and integration of components. The solution can be used to analyze the functional performance of the mechatronic systems from the preliminary design stage. This includes optimizing the complex interactions between the mechanical, hydraulic, pneumatic, thermal and electrical/electronic systems before the first physical prototype, avoiding design flaws and improving the product’s overall performance and quality and proactively exploring new, innovative designs.
By using Simcenter Amesim during the verification stage, Spit Paslode has enabled the R&D office to focus on the pre-project phase to assess different technologies, explore new avenues and extend its use to pneumatic and electrical tools.