Succeeding with open-source-software in product development
Because developing and building machines is a mistery for many engineers in the european union, our author has created this guide for mechanical engineering start-ups. It demonstrates, how the product development process for machines can be efficiently implemented using freely available software.
The process described in this tutorial is based on established standards from the industry.
This guide is based on VDI 2221 'Development of technical products and systems - Model of product development' and follows the steps of the product development process, from the machine's requirements to the signed declaration of conformity.
This guide is an english translation of the German article "Leitfaden - Wie der Produktentstehungsprozess mit Open-Source-Software gelingt" from the engineering trade magazine "konstruktionspraxis"
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Step 1: Requirements - The Starting Point of Product Development
The requirements for the machine to be developed are defined as a result of market research in the form of a requirements list. The goal of the market research is to identify the requirements customers have for a specific machine. The requirements list consists of at least the columns 'No.', 'Description,' 'Type' (Mandatory Requirement, Minimum Requirement, Desired Requirement), and 'Value.' It can be easily created in a LibreOffice Calc spreadsheet.
Software used: LibreOffice Calc
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Step 2: Choosing the Technology - Not Just Patents and Utility Models
With the requirements from market research, a suitable technology can be selected. For strategic reasons, it is advisable for start-ups to initially focus on technologies that are in the public domain, meaning they are no longer part of the protected state of the art. This ensures that start-ups are safe from infringement.
The protection period for patents is typically a maximum of 20 years, for utility models a maximum of 10 years, and for industrial designs (designs) up to 25 years. Although industrial designs do not protect technologies, it is still important to keep them in mind.
Public domain technologies can be found in patent databases, scientific publications, and old product catalogs. The search results are filtered to display only technologies that are over 20 years old.
The following are proven sources for obtaining this information:
- Espacenet (For patent documents)
- Lens.org (Allows for quick identification of key inventions within a niche based on the number of citations of patent documents)
- Springer (Publisher of research papers and books e.g., The International Journal of Advanced Manufacturing Technology for mechanical engineering)
- eBay (Old product catalogs and handbooks)
- DesignView (registered design database)
The results of the technology research are compiled into a LibreOffice Calc spreadsheet. For quick reference, the table should at least include the invention's title, a brief description, a preliminary assessment of its suitability for meeting the requirements, the publication date, a representative graphic, and a link to the source.
Once one or more technologies are selected from the list based on their suitability for the new product, these should be reviewed by a qualified patent attorney through a 'freedom-to-operate' patent search.
If the development starts with an existing product found, for example, in an old product catalog, it can be analyzed to better understand its functionality. For this, a black box is created that identifies the main function along with the energy, material, and signal flows as inputs and outputs. Subsequently, the main function from the black box is further detailed in a functional structure.
Software used: LibreOffice Calc
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Step 3: Product Concept - Understanding the Technology Behind the Product
From the technologies selected in the previous step, an overall concept for the product is created. This can be drafted as a simple hand sketch on paper. Alternatively, the overall concept can be assembled using basic shapes in LibreOffice Impress. Precise dimensions are not relevant at this stage. However, all environmental factors, such as forces or ambient temperatures, should be clearly indicated. Specific values for these environmental factors do not need to be determined yet if they are not known at this point.
Software Used: LibreOffice Impress
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Step 4: Conformity - Developing and Manufacturing Safe Products
With the finished product concept, the product is assessed in terms of product safety. For products placed on the market in Germany, the Product Safety Act (ProdSG) applies. This law stipulates that all relevant directives, standards, and other requirements for product safety must be identified.
To bring a safe product to market, a risk assessment must be conducted, among other things. It is advisable to involve people from different areas within the company (e.g., mechanical engineers, electrical engineers, sales, technical support) in the risk assessment process.
Laypersons, in particular, can provide great value in the risk assessment, as they can easily put themselves in the role of a user. The goal of a risk assessment is to identify all potential hazards associated with the product and to formulate appropriate measures to reduce the risk to a tolerable minimum. The risk assessment must be maintained throughout the entire product lifecycle to include any newly identified hazards. A risk assessment can easily be created as a LibreOffice Calc spreadsheet.
To quickly find information in the sea of product safety documents, Large Language Models (LLMs) that provide citations are useful. These LLMs are not used here for generating specific answers but are employed as search engines. This way, employees can obtain the necessary information in just a few seconds, without having to read hundreds of pages from different documents. A more basic method for quickly searching relevant documents is the search function in PDFs, where key terms can be searched for. However, with this method, each document must be searched separately.
Additionally, an operating manual is created for each machine. The operating manual is created in LibreOffice Writer.
At the end of the machine development process, the entrepreneur or a person designated by them signs a declaration of conformity. The designated person assumes part of the responsibility of the entrepreneur. With the signed declaration of conformity, the entrepreneur certifies that the machine they have built meets the minimum safety requirements according to the state of the art. The state of the art regarding safety is, among other things, defined in standards. The declaration of conformity is created in LibreOffice Writer.
Software Used: LibreOffice Calc and LibreOffice Writer
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Step 5: Preliminary Design - Calculations for the Product Concept
The goal of the preliminary design is to determine as many values of the product as possible. This includes insights from product safety documents, where, for example, minimum requirements for safety factors can be specified. These safety factors can then be determined using standard strength calculations. Additionally, this step involves determining most of the product's dimensions, as well as those of its individual components, ensuring that all parts fit together.
The calculations from the preliminary design can also be directly used to create geometries in 3D CAD. However, in most cases, a custom Python script needs to be written in FreeCAD. A preliminary design can be created in a LibreOffice Calc spreadsheet.
Software Used: LibreOffice Calc
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Step 6: Detailed Design - Fully Defining the Machine
The goal of the detailed design is to create all the necessary documentation for the manufacturing of individual parts and assemblies. Using the parameters from the preliminary design, 3D CAD models are created. As many requirements from product safety are simulated as possible, for example, using Finite Element Analysis. Technical drawings are derived from the 3D CAD models.
3D CAD
The 3D CAD models of the individual components are designed in FreeCAD within the Part Design workbench. The Part Design workbench follows the sketch- and feature-based solid modeling process, which is also used in many other 3D CAD programs. Each individual component is saved in a separate FCStd file so it can later be managed in a PLM system.
Assemblies are created from the individual parts. In a top-down process (skeleton model), the Assembly 4 workbench in FreeCAD is used. In a bottom-up process, the A2Plus workbench in FreeCAD is used.
Technical Drawings
There are several types of technical drawings. The technical drawings most commonly created by manufacturers are the manufacturing drawings for individual parts and the assembly drawings for assemblies.
In the FreeCAD Tech-Draw workbench, the required technical drawings are derived from the already created 3D CAD models. A variety of sheet templates following different standards can be used. The views are placed on the sheet after selecting the template and can be annotated, for example, with dimensions or notes.
The completed technical drawings are exported as PDF files and integrated into the PLM system, where employees from the manufacturing department can access them.
Alternatively, the technical drawings can be sent as PDFs to subcontractors who will then take over the manufacturing process.
Simulation
By simulating the individual parts, as many tests as possible can be replaced. For example, the safety factor of a component can be calculated via simulation before the part is even manufactured. This reduces development costs and shortens the time to the finished product.
For the calculation of the safety factor, the open-source software Pre-Po-Max is used, which allows the simulation of load cases for components in great detail.
The results of the simulation are documented in LibreOffice Writer and serve, among other things, as proof to authorities in case of any damage events.
Software Used: FreeCAD, PrePoMax and LibreOffice Writer
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Step 7: PLM - Organizing Product Data throughout its life cycle
All product data is organized in a central location throughout its entire lifecycle, ensuring secure access for all employees. This prevents the creation of duplicates, which could even contradict each other.
Network
All product data is stored on a central computer within the company. All other computers are connected to this central computer and can access the data. Additionally, access rights can be set so that employees can only access the data relevant to them. The central computer has redundant storage and an independent power supply to ensure no data is lost in case of a power outage. Furthermore, the data is regularly backed up to an external storage device.
Versioning (Subversion and Tortoise SVN)
Versioning allows for hierarchical traceability of changes to files. The versioning software Subversion is installed on the central computer. The Tortoise SVN client is installed on all other computers, enabling files to be checked out by one employee and later released. This prevents multiple employees from working on a file simultaneously, which could lead to conflicts.
Parts Management
All components, whether produced in-house or supplied by external vendors, are managed in an overview to allow for cost calculations and availability tracking. This overview is created in a LibreOffice Calc spreadsheet.
Software Used: LibreOffice Calc, Subversion (SVN): VisualSVN, Tortoise SVN Client
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Step 8: Manufacturing - From Theory to Practice
The manufacturing process produces the machine based on the designs. Once all the documentation for the designed machine is available for production, it can either be done internally or outsourced to subcontractors.
Weighing Between In-House and External Manufacturing
The advantage of in-house manufacturing is the higher protection of intellectual property and less dependency on other companies. One of the disadvantages is the higher initial investment costs. Therefore, each entrepreneur must decide which solution is better for their case. This decision can also change during the course of the project. For example, prototypes can be manufactured in-house first, and then the series production can be outsourced. The reverse approach is also possible. It is also possible to outsource only parts of the manufacturing process. Outsourcing "dirty" manufacturing steps, such as casting, can be beneficial to reduce the burden on in-house employees.
Quality Assurance
The manufactured components and assemblies are tested for safety and functionality. The exact requirements evolve throughout the project and may also change after serial production based on customer feedback. Safety testing helps avoid liability for personal injury and property damage due to insufficient safety measures. The functionality testing ensures that the product performs as intended.
The results of the tests are recorded and stored in LibreOffice Calc.
Software Used: LibreOffice Calc
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Step 9: Summary
This article aims to show how product development can be implemented using freely available software. The following software solutions are used:
- FreeCAD
- PrePoMax
- LibreOffice Writer, Calc, and Impress
- Espacenet
- VisualSVN and Tortoise SVN Client
Large engineering companies use much more complex software for the product development process. However, the process presented here is more than sufficient for small and, in some cases, medium-sized engineering companies. The goal of this guide to product development using open-source software in mechanical engineering is to provide startups with all the necessary tools to establish their engineering business with minimal financial risk, thereby driving innovation.
If you want to learn more about the product development process in mechanical engineering, let's connect!
