Driving Lean Manufacturing with Digitalization
Reducing waste in the manufacturing process is always a challenge, especially when it comes to new product introductions (NPI). It is a key pain point for manufacturers, as waste leads to delays, unexpected costs, quality issues, and lost profit. Waste isn’t always about material that must be discarded—it can also include idle workers and equipment, unused material, and inefficient planning processes.
Lean manufacturing tackles the problem of waste in the manufacturing process, wherever it occurs. To consistently reduce waste and apply lean manufacturing principles, manufacturers need an IT system—including both PLM and MOM—that enables better collaboration, maintains, and utilizes organizational knowledge, monitors lean KPIs, and helps the organization achieve first-time-right design and production for all products.
First-time-right with the Digital Twin
PLM and MOM systems allow manufacturers to digitalize production and create digital twins of products, processes, and production lines. Using digital twins, manufacturers can conduct trial and error in a virtual environment and rectify any problems before they reach manufacturing. The virtual fixes save valuable time and resources like energy, machine time, and production materials. Importantly, they also advance the ultimate lean manufacturing goal—first-time-right manufacturing. When a manufacturer can produce a product right on the first attempt, production becomes much more efficient and predictable. This eventually leads to cost optimization, shorter time to market, and better resource utilization without reducing the quality of the products.
Digitalization of PCB Assembly NPI Process
Digitalization can also play an important role in making the PCB assembly NPI leaner for electronics manufacturing companies. Siemens PLM software has made this its mission, providing a suite of applications on the Teamcenter platform that help manufacturers build a digital twin for the entire product lifecycle, including both electronics and mechanics. Valor Process Preparation, in particular, allows manufacturers to digitalize the PCB assembly process as a one-stop shop and make it extremely efficient and lean.
Standardizing and Enhancing Design Data
Reading the Design Data
The first task of the PCB assembly process engineer is to read the design data. It sounds like a straightforward task, but when done manually, mistakes are common. Often, the design data of the wrong PCB is uploaded, or the engineer reads the wrong configuration of the PCB, or reads unreleased design data. Any one of these mistakes can result the wrong PCB being produced, forcing manufacturers to scrap an entire batch.
An EMS faces an additional challenge when reading PCB designs. Since their customers send PCB designs in different formats, the EMS must be able to read designs in multiple different formats. This is a technical challenge that can impact time to market and product quality. It takes time to convert the design data into the EMS IT system’s format and the conversion is susceptible to human error.
Digitalized solutions solve these challenges and ensure that the right design data is automatically delivered to the process engineer. These solutions also enable production in different sites according to logistic requirements such as component supply, production line availability and delivery destination. They also make it easy to convert design formats so EMSs can work with any data format their customers send.
Defining Physical Shapes of the PCB Components
The PCB design does not typically include the accurate geometry of the components assembled on the PCB. This poses a challenge for the assembly and test of the PCB plans, as it is impossible to create assembly work instructions and assembly programs for the SMT machines without knowing the exact shape of the assembled components. Therefore, before planning the PCB assembly process, the process engineer must first search different libraries to find the accurate shapes of all components. A digitalized solution with pre-existing part libraries can significantly mitigate this challenge, enabling the automated update of all PCB components with accurate geometrical representation in the digital environment. This accurate “digital twin” of the design results in better decision-making when planning the assembly process and supports first-time-right assembly while shifting the planning decisions left to an early stage of the process planning.
%%https://player.vimeo.com/video/611882927%% Video: Watch how Valor Process Preparation makes it easy to standardize design data.
Validating Design Manufacturability
After converting the design into a digital format and creating an accurate representation, the process engineer performs Design-for-Assembly (DFA) analysis in order to validate that the design delivered by the PCB designer is manufacturable. This process is a challenge in and of itself, as there are thousands of validations to perform. Sometimes not all the information is available, so the process engineer can’t perform all necessary validations at this stage. In addition, the validation is very time-consuming and prone to human error. Every error at this stage can affect the yield rate in production and increase the costly rework and scrap rate.
A digitalized solution allows the process engineer to run all the required validations in an automated manner. The automation eliminates the risk of human error and makes it possible to perform all validations in a manner of seconds.
%%https://player.vimeo.com/video/611882888%% Video: See how automated validation tests enable a process engineer to confirm manufacturability of a specific design.
Stencil Design
After the design is finalized and validated, the process engineer designs a stencil to support the manufacturing requirements of the PCB. Poor stencil design results in multiple production issues—in fact, stencils are responsible for a large majority of manufacturing errors in PCB assembly manufacturing. Therefore, first-time-right stencil design is critical. Since stencils are typically manufactured by a supplier, it also takes time to manufacture and ship the stencils, often causing production delays.
A digitalized solution makes it possible to design the stencil in a digital environment using a re-usable set of rules to validate the quality of the stencil design and verify that the stencil can support the PCB assembly manufacturing requirements. The automation results in faster stencil design and eliminates many production issues that result in scrap or rework.
%%https://player.vimeo.com/video/611882932%% Video: Watch how Valor Process Preparation validates a stencil design.
Automated and Manual Assembly Planning
Defining Assembly Technology for Each PCB Component
After confirming that the design is manufacturable using the production line technology, the process engineer defines the assembly technology for every PCB component. As there can be hundreds or thousands of components on a single PCB, this process is also lengthy and error-prone when done manually.
Digitalized solutions automatically define the assembly technology while also considering the technology available on the production line. The automated technology definition saves significant time in the NPI process and prevents human error that can result in scrap or rework.
Authoring Assembly Work Instructions
After defining the assembly technology for all the components, the next step for the process engineer is to author the work instructions for assembly. This too is very time-consuming, and it is nearly impossible to ensure that the work instructions are always aligned with the most up-to-date process plan.
With a digitalized solution, updated work instructions are generated automatically. The automation enables paperless work instructions on the shop floor, which are always in line with the latest process design.
SMT (Auto Assembly) Machine Programs
In parallel to work instruction authoring, the process engineer generates programs for the SMT machines so the machines can rapidly assemble all PCB components on the PCB. One of the challenges in this step is that the process engineer often needs to use the physical machine to generate the program. This presents a challenge because the production line must be shut down while the process engineer is working on the machine program, and nothing can be manufactured on the line during that time.
In addition, the process engineer must be near the SMT machine. The company cannot utilize a central process engineering department and must have process engineers on-site in every production facility. Another challenge arises when the process engineer wants to move production between lines. As every machine vendor uses different software to program the machines, the process engineer cannot reuse programming from the original production line and must redo everything from scratch.
A digitalized solution enables offline programming of SMT machines, eliminating the need to occupy the physical production line when programming the SMT machine. What’s more, the process engineer can generate machine programming from anywhere in the world.
%%https://player.vimeo.com/video/611882960%% Video: Watch how Valor Process Preparation works with all types of Pick & Place machines to effectively manage data.
Process Validation
Before the process plan is released to the shop floor for execution, the process engineer must validate that the assembly has been implemented correctly. A sticky tape analysis is performed in which the production line is used to place the components physically on sticky tape. This occupies the production line and halts production.
A digitalized solution enables a virtual sticky tape analysis that digitalizes the entire validation process. Performing the analysis on a digital twin is much faster, does not require any physical assets, and the production line can continue production while performing the analysis. The analysis can be done anywhere, even from home or on another continent.
Inspections and Testing
Quality and test engineers must ensure that the process supports the production of PCB assemblies with the required quality by using a set of inspections and tests conducted during the production process. These include solder paste inspection (SPI), automated optical inspections (AOI), automated X-ray inspections (AXI), manual inspections, and in-circuit-tests (ICT). A digitalized solution supports the full digitalization of test and inspection definition. Eventually, it produces the machine files and the manual work instructions to perform these tests automatically, as part of the route.
%%https://player.vimeo.com/video/611883147%% Video: Watch how the test assembly section in Valor Process Preparation manages electrical testability and test programming.
Release the Route
Releasing Production to the Shop Floor
After the planning and validation work is completed, the process engineer releases the work to the shop floor. This is typically done via email and/or by uploading files to the company’s network. These methods of data delivery are susceptible to error, as both the process engineer and the shop floor manager can send or use the wrong production plan on the shop floor. They also pose a security risk as the production plan can be accessed by unauthorized people in the organization.
A digitalized solution, integrated with the PLM system, enables an automatic and controlled release to the shop floor.
%%https://player.vimeo.com/video/611883265%% Video: Watch how Valor Process Preparation releases data once all the files for the different aspects of the assembly collateral have been created.
Applying Lean Manufacturing Standards in Your Organization
Valor Process Preparation is a fully digitalized solution that addresses all the challenges discussed in this article. Integrated with Teamcenter, Siemens’ PLM solution, Process Preparation can fully digitalize the process, from the receipt of the design data from the PCB designer to the completion of the process engineering when all machine files and work instructions are sent to the shop floor.
Whether you are an OEM or an EMS digitalizing your manufacturing and applying the digital twin concept, Process Preparation can help you make manufacturing and design decisions early in the manufacturing process and reach production with confidence in the design and process planning. This leads to leaner and more efficient production and improves competitiveness, through improved cost, faster time to market, and higher resource utilization.
Kobi Levi is the business development manager for Siemens Digital Industries Software.
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