Computer-Aided Design (CAD) has solidified itself as a tool at the cornerstone of almost all design data produced for manufacturing across all types of industries. Whether your company is manufacturing a pen or an airplane engine, the journey of your product lifecycle is likely to begin on a computer screen.
While the benefits of CAD are well-documented and would be helpful for both Bic and Boeing, the less glamorous side is not often discussed - the enormous volume of data that it produces and the complex data management it requires.
Companies with hundreds of products may have thousands, sometimes millions of parts, assemblies and drawings. Some of those companies have been using 3D CAD for decades without any formal or automated method of managing all those data files, relying on manual methods, standard folder structures on shared network drives, historical procedures and tribal knowledge. However, in many companies, the same process that was used to manage paper drawings has simply been replicated digitally using files and Product Data Management (PDM) software. There now might be less physical clutter, but the organizational chaos hasn’t gone away and PDM issues remain ever so common.
Managing the mountains of product design data can result in a significant investment in IT infrastructure.
Keeping track of the mountains of data produced by your design teams and your CAD system can soon become overwhelming. A simple project containing just 10 assemblies, 40 parts and a drawing for each, produces 100 individual files on your hard drive for every version and revision of the design. Before you know it, those 100 files become thousands. The margin for error increases exponentially at an alarming rate. It only takes a few costly mistakes, project overruns, or product recalls to ruin your company’s reputation.
Because CAD files are saved on some form of digital storage media – either a local hard drive, a shared network drive or (if transferring data) an email server or USB drive – the odds of files being overwritten, lost, stolen or corrupted are stacked against you. Engineers and other project stakeholders waste countless hours searching for data and addressing version control issues. With more data silos spread across different media in different locations, it’s too easy for teams to accidentally work on copies of the wrong version of a design without even realizing it.
Trying to manage so many copies of so many files leads to unreleased or incorrect versions of designs finding their way to sales, manufacturing, external suppliers, or your competition, with disastrous results.
PDM software does indeed provide many benefits – reducing the number of errors and frustrations detailed above – however, it comes with a hefty price tag. There is the initial outlay, ongoing maintenance payments, training and consultancy fees to get you up and running, plus the dedicated servers and IT infrastructure requirements that are not included as part of the original quote.
The Perils of PDM
Despite what most CAD vendors say in their marketing materials, CAD was never built with collaboration in mind. The fundamental issue preventing collaboration with CAD data is that only one person can edit a file at any one time. If an application does let more than one person open the same file at the same time, it usually makes a copy of the file on-the-fly so that any changes do not affect anyone else. This, however, defeats the purpose of collaboration – as each person is working on different copies of different files. Additionally, PDM's reliance on slow file check-in/check-out can create bottlenecks in the product development process. When a file is checked out, it is locked and can’t be edited by other users until it is checked back in. The reason why files are locked when opened by an application is to prevent:
File Corruption – If you were to have more than one person trying to write on the file at the same time, there would be data structure conflicts that could not be resolved – and the chances that the file would become corrupt are very high. Once a file becomes corrupt, both the CAD system and the operating system are unable to decipher which data is correct, and can’t untangle any malformed data structures. The file is then flagged as corrupt and unusable.
Lost Work – If more than one application has the same file open at the same time for editing, you are at the mercy of the “last save wins.” The hours you may have spent carefully modifying a part or an assembly are wasted because somebody else, editing it at the same time, saved their work after you saved yours. The next time you open that file, everything looks completely different and all of your hard work is lost forever.
When there is only one designer on a project, managing all the generated CAD files using a set of folder structures on a hard drive may be manageable with due diligence. However, that is not a realistic scenario. The only way to effectively keep lead times short while innovating the next great product idea is to employ teams of designers, contractors and external suppliers while keeping sales, marketing, management and customers in the loop as well. This is when collaborating using files becomes a problem.
To avoid any such conflicts, individual design tasks can be assigned to different engineers working on the same project in an attempt to prevent anybody from working on the same files at the same time. However, all the changes made to each file must somehow be integrated into a master top-level assembly. That means that at some point – probably several times a day – somebody must open the top-level assembly to check that all the subassemblies and parts are behaving as expected and attempt to resolve any conflicts that arise.
Without any formal PDM software, it’s impossible not to step on each other’s toes, overwrite somebody else’s work, or completely break everything.
It’s also impossible to know if somebody is editing a file, who that person is, or if all the files are saved and up-to-date. This means that any person who needs to access those files could be viewing incorrect data and all sorts of problems could ensue.
The Drawbacks of File-Sharing Services
File-sharing services, such as Google Drive or Dropbox, are very popular and enable users to send files of any size very easily. Files can either be copied into a special folder on your hard drive that automatically syncs with the service in the cloud, or you can upload files using a web browser. The recipient only needs to click a link to download the file locally.
Security – File-sharing services have extra security when data is stored on their servers and when data is being transmitted. You can also add password protection. However, how do you send that link and password? Over unencrypted email? In addition, a survey from Osterman Research found that 69% of employees regularly use their own personal file-sharing account to store and send sensitive company data. Of the respondents that had since left a business, 6% admitted to sharing that data with their new employer or others! Once the end-user has the file, they can do anything they want with it as per email and FTP.
With any method of transmitting data files, there are concerns around security, mistakes and uncontrolled copies. File type and file version can also be an issue. If the recipient is not on the same version of the same software as you, then they will not be able to open the files. You must, therefore, make sure that the files you send are compatible with whatever system they use. If they only need to view the files, they will need to download and install compatible viewing software.
The Drawbacks of PDM
Having to check a CAD design in and out from “the vault” is a major flaw in PDM systems. Once an external party has your files and they are able to open them and work on them, you can do nothing but wait until they have made their edits and have sent the changed files back to you (using one of the same methods outlined above).
It is also impossible to know what changes are being made if any. Since your partners are not local to you, you cannot just walk over, look over their shoulder and ask questions. This requires regularly scheduled design reviews, which often can be disruptive and time-intensive. When deadline day arrives, their final edits may not be what you were expecting. This is wasted time that is difficult to quantify.
Exchanging CAD files using manual methods is not scalable for large design teams or even modest teams with multiple locations.
Each team has their own processes and rarely communicates with each other, leading to duplicate data, information silos and islands of automation. When several copies of the same part are spread across different systems at different locations and a change is required, it’s virtually impossible to know which file is the master copy and who should be making the change. Changes are often made to one copy, but not to others. Mistakes are easily made.
The importance of early collaboration with everyone in the supply chain cannot be stressed enough. Getting early feedback at every stage of the design helps you to manage and reduce product-related costs, manufacturing defects, recalls, complaints and risk.
All of the above issues underline the need for good working practices and secure PDM. The level of automation, management and data security that is provided by the data management solution you choose depend on the route you take.
(This article was originally published on September 16, 2019, and updated on December 19, 2022.)