Mitsubishi Agricultural Machinery (MAM) first used 3D data to model parts for the combine harvester product line. Soon, they started leveraging the same 3D data with PTC/Creo and Lattice Technology's XVL applications to optimize the assembly process of the combine harvesters. It was difficult to share the 3D CAD data outside of the design division because of the very large model sizes and having many different CAD files to make up the entire product. That is what led MAM to use XVL. Since then, MAM has expanded its use of XVL for downstream applications by stakeholders throughout the company.
Planning and Validating the Assembly Processes Using XVL
When MAM introduced 3D into its product development, it was difficult to use downstream because the company was still deeply entrenched in delivering assembly process information using paper reports and drawings.
The design, product planning and production divisions, which are responsible for manufacturing planning, continued to use the traditional 2D methods, long after 3D was introduced. This caused delays and frustrations. For example, the product planning division waited for delivery of approved hard copy drawings from the design division, and the production division then waited for the hard copy assembly process management sheet. This resulted in long delays as the work of manufacturing planning had to wait until they received each division's paper instructions.
By using XVL, MAM was able to change from a paper-based process to an electronic-based process, resulting in shortened lead times and a reduction in inventory. The new process is known within the company as the "Flexible Manufacturing Method."
This method uses the assembly BOM (commonly called the mBOM) to track part-level information such as suppliers and inventory. This is quite different than the eBOM that is created from the structure tree as designed in Creo.
MAM uses Lattice Studio to create and maintain the assembly mBOM in XVL. XVL and Lattice applications support multiple bills of material (eBOM, mBOM, sBOM, etc.) so that the same model can be used for different applications without changing the structure.
This assembly BOM created within XVL is then forwarded to the MAM Mix Production System (MIPS), which manages the parts procurement process automatically.
In the product process planning phase, the following problems were identified and XVL was used to resolve them:
- Little or no collaboration with the design division
- Neither the entire assembly structure nor the assembly process planning procedure can be viewed
- Creating the 2D illustrations for the assembly process sheet is time consuming and design changes are not included because of the inability to update and share data quickly and easily.
Objectives for Using XVL in Production Planning
MAM had two objectives for using XVL in production process planning. One was to "front-load" the process design using the assembly tree structure in XVL to find and resolve production issues as early as possible. The second was to reduce the time to generate assembly process instructions by automating as much of the process as possible.
"Mitsubishi picked XVL for production process planning because it is lightweight, accurate and has excellent 3D performance," said a company spokesperson. Furthermore, XVL applications make it easy to create assembly process instructions. As an added benefit, XVL is flexible and can be used to improve business processes throughout the organization - from design all the way through to sales.
New and Improved Production Planning Process
Prior to implementing XVL, assembly process planning was only undertaken after receipt of approved drawings. With XVL, assembly process planning now takes place during the design phase so assembly issues can be found and resolved before the design is complete. In addition, MAM has been improving productivity further by creating work instructions directly for the shop floor that are authored and saved inside the XVL file.
MAM now uses XVL for assembly process planning and creating work instructions. Assembly process planning has four steps:
Create the assembly tree structure (mBOM)
Define work processes
Allocate shop floor resources
Export the assembly tree (mBOM).
Initial Manufacturing Planning - Stage 1
In stage 1, MAM designs the basic assembly processes in XVL Studio, grouping parts to be sub-assembled in the basic assembly process. Later, the order of the assembly can be changed as required for detailed manufacturing process planning, and parts can be added or repositioned with XVL Studio.
Since it is quite difficult for one person to cover the entire assembly, this work is shared and divided among planning team members. XVL Studio makes it easy for team members to merge process trees and add sub-assembly processes to quickly create the whole assembly process.
Man-Hour Calculations - Stage 2
Before XVL, MAM used Excel to handle man-hour calculations and critical assembly instructions. Now MAM maintains such information as attributes in the XVL file, making it easy to calculate man-hours and generate assembly instructions.
Resource Allocation - Stage 3
In stage three, shop floor resources are allocated to each process. Line shares and shop floor allocations can be done rapidly.
Assembly Plan Validation - Stage 4
Stage four is delivered via basic customization of XVL Studio, allowing Mitsubishi to easily identify the assembly structure and parts attributes, and to verify the line loads using the man-hour calculations.
Process Instruction Creation - Stage 5
MAM uses XVL Studio to create process animations and then take snapshots of the animations to be used as illustrations for the process instructions. XVL Studio also makes it easy to annotate the snapshots with critical process information.
Process Instruction Export - Stage 6
MAM has customized XVL Studio with an export function to output the saved snapshots and process information. The exported information is saved directly in an assembly process information sheet.
Results
By changing the assembly process planning and work instruction methods, Mitsubishi achieved gains through faster planning and better process design. However, the methods for making work instructions needed to be reviewed as the creation of the snapshot of the work instructions proved to be very time consuming.
The company has received positive reactions from the engineers responsible for assembly process planning. Namely, that this new system allows them to view the whole assembly process in 3D, which makes it easier to design each individual assembly process.
Expectations for 3D data use on the shop floor have been rising since XVL can show assembly structures, assembly processes and work instructions. This has motivated shop floor staff to change their attitudes toward 3D as a tool instead of sticking to conventional methods.
For more information contact:
Lattice Technology Inc.
Westmoor Technology Center, Building 10
11000 Westmoor Circle, Suite 170
Westminster, CO 80021
720-330-3197
www.lattice3d.com