I’ve Had Many Clients ask me “What is a STEP File”? So I thought I would explain…
Let’s begin with an analogy. You’re probably familiar with Microsoft Word documents and with PDF files. Often times, you create a document using Word, then save (or print) it to PDF before sharing. PDF is more universal and not easily edited. It’s basically a snap shot of that Microsoft Word document at the time you saved it.
That’s effectively what a STEP file is to 3D engineering model data. It’s one of several universal formats we use to communicate between CAD systems. I’ve run into many clients that come to me because they “need a STEP file.” In reality, the vendor needs engineering data and could likely accept it in several formats – STEP just happens to be one of the most common.
Why Use Universal Formats like STEP?
In most cases, we introduce some revision control into the process, so the supplier gets a STEP file marked as “Rev A” or similar. This ensures that when we make changes down the road, we’ll have confidence that our supplier is quoting (and manufacturing!) the part at the correct revision level.
Comparing it back to the Word Document to PDF comparison – it also mitigates risk of the part geometry getting modified accidentally. The SolidWorks files are editable in SolidWorks. This means that your engineer (or your vendor) could screw up and accidentally change a detail and overwrite the old file. The best way to mitigate this kind of risk is to create incremented revisions (Rev A, Rev B, etc) saved out to a non-editable format – such as STEP.
How Does a Vendor Use a STEP File?
The vendor will import the 3D geometry into their tool chain. For a process such as 3D printing, the quoting has become mostly automated. Simply the upload the part into the vendor system and you’ll get instant quotes for a variety of materials.
In manufacturing, just about any modern production process will begin with a 3D model of the part to be created. Manufacturing engineers will use the model to design the tooling and/or machine paths necessary to produce the part.
Sounds Easy. How do I get a STEP File Then?
Remember, the STEP file is the final output of some design process. We create the STEP file when we are ready to prototype or manufacture some component. The act of creating the STEP file is as simple as clicking “save-as” within your CAD software of choice. Designing a part that meets its intended requirements, and is appropriately detailed for the manufacturing process it is intended for, is where the real work lies. A well designed part could quite literally save you thousands and thousands of dollars in tooling and manufacturing costs.
Can small engineering and design firms afford CAD collaboration? That was the question Jim Brown addresses a brand new e-book over at Tech-Clarity. I had the pleasure of speaking with Jim on the phone to discuss how modern CAD collaboration tools are dramatically improving the work flow of small service firms like Zalaco, and providing better value to the clients we serve.
If you’re trying to figure out how to manage CAD data you need to solve two problems:
Data Backup: Needs to be (almost) real time and invisible to the user.
CAD Specific Issues: Versioning, Revision Control, and Collaboration
Ok, so item #2 is more than one problem. Fortunately, any system designed for CAD data should handle those out of the box. Unfortunately, real time (or regular) data backup is not something that meshes well with a good CAD data system.
Product Data Management (PDM) systems built for CAD work on a “check in” basis. They typically save every single version a user ever checks in. These officially checked in versions become the basis of collaboratively working on the same assembly in CAD. If a bunch of users were just working out of the same network drive, you’d perpetually be stepping on each others toes and overwriting each others files.
However, in the real world, we do a lot of work we don’t want to check into the official system for a myriad of reasons. As a result, we need to know that all of that “in work” data is safe and backed up somewhere. For this purpose, a traditional data back up system works just fine.
My two pronged solution is incredibly powerful yet exceedingly simple.
DropBox provides real time backup of everything I do.
GrabCAD Workbench gets the official “updates” that I need to maintain version control on, share with a client, or mark as an official revision.
As a single user, they play together nicely. DropBox and GrabCAD are syncing the same directories without significant issue. However, this is a single user environment and sure it would wreak havoc if two users were doing the same thing with the same file sets
So that’s that! I love consulting on CAD Data and PDM issues, and I love the challenge of getting data into the cloud, so please feel free to contact me if I can be of service!
If you’re background is not one that has you familiar with commonly used terms in mechanical design, mechanical engineering, product development, CAD, or manufacturing, this page might be useful to you.
Basically, it’s intended to be a laypersons guide to the words and phrases that I’m used to using on a daily basis. This is mean to give you just enough information to be dangerous, or more importantly, have a basic background before you approach someone for help in this area. Feel free to add suggestions in the comments for other words and phrases and I’ll do my best to keep this up to date. The goal is to keep this “un-technical” with links to more detailed information. It is by no means all encompassing and I will be adding to it over time. Please use the comments to make suggestions for the list (corrections, new terms, recommended links, etc). Thanks!
Backlash: The “slop” felt in a mechanical system, typically when the system reverses direction. Parts require clearances to assemble correctly, and these clearances can be felt in moving assemblies. (Wikipedia)
Bearing: A bearing helps things move. Typically, bearings make it easier for parts to slide or rotate, and to do so for a long time without wearing down. (Wikipedia)
Boss: A generic term that describes something that sticks up on a part. An plastic part may require a hole for a screw, so the designer will add a round boss to make room.
Bushing: Sometimes used as a bearing, a bushing is typically a hollow cylinder used as an interface between a hole and a shaft.
Datum: A datum is a reference feature that helps you interpret dimensions on an engineering drawing. (Wikipedia)
Detailed Design: Going from high-level conceptual design to something that can be manufactured. This typically includes drawings for all of the parts and assemblies required.
DFA: “Design for Assembly”. In other words, how easy will this thing to be to put together? An elegantly placed screw may not seem so great when you realize there’s no way for a screw driver to reach it. (Wikipedia)
DFM: “Design for Manufacture”. By understanding how things are going to be made, you can design them to better accommodate these manufacturing processes. It’s not uncommon for an inexperienced engineer to make parts unnecessarily expensive by creating features in their 3D model that are not ideal for the intended manufacturing process. (Wikipedia)
Drawing: When I say “drawing”, I’m referring to a technical document that describes the necessary information to produce a particular part or assembly. Drawings come from CAD packages and conform to commonly accepted standards.
Industrial Design(er): Industrial design tends to refer to the look, feel, and human interaction with a product. Often times an industrial designer will be responsible for developing the look (shape, color, textures) of a product. Mechanical engineers design the functional product around these constraints.
Iterative Design: Even when you think you know exactly what you want, the process of designing, prototyping, and testing will always produce changes. You should expect this to happen.
PDM: “Product Data Management.” Exactly what it sounds like, managing all of the data associated with a product like 3D models, drawings, manufacturing plans, etc. (Wikipedia)
Pitch: Typical of screws and gears, it describes the numbers of threads or teeth over a given distance. For threads or gears to properly mate, they must have the same pitch.
Preload: A 50lb weight sitting on the ground has a 50lb preload to the ground. It will require at least 50lb of force opposite the ground to break contact. In mechanical assemblies, things like bolts and springs are used to create preload to ensure things stay where they are supposed to.
Prototype: Simply a mock-up of the desired end result. This can be done digitally, with 3D models, renderings, and animations. It can also be done physically using tools like 3D printers.
Rendered Image: Using 3D CAD data to generate realistic images of a design, product, or idea. Rendered images simulate the behavior of light and typically take hours to generate at high resolutions. Many product images you see in advertising and on web sites are actually rendered from 3D data, even though they may look like a photograph.
Rendered Animation: CAD data can be used to demonstrate a products function, how it goes together, or just move it around in space. When we render each frame of the animation, we can bring ideas to life on the screen.