It's kind of a miracle that the output files from all the solutions are standardized and work across the industry to automate production and you can get a PCB made for $1. In the mechanical CAD/manufacturing world there is a LOT of manual work and discussion required. There are now automated quoting services, but they just put the onus on the user to upload files and manually input details into a proprietary system.
I'm not an expert for mechanics, but isn't what you discuss for mechanics usually tolerances or properties that are not directly involved in the outline of a part, such as materials used or roughness?
This stuff you still need to discuss. It's just that the basics are often enough. But, in my experience, if you want less than 0.3 mm tolerance on your PCB outline or a component needs a certain soldering cycle or method, you better tell your PCB manufacturer and you better do it on the phone, they may or may not look at the drawings. Once we only accidentally discovered that an isolator in a medical device was soldered using a temperature profile that exceeded its maximum temperature and thus the isolation was no longer guaranteed by the manufacturer.
Yes, tolerances and other things need to be discussed. STEP files can technically convey most of these things, but in practice most MCAD software cannot output these details to STEP files, and most machine shops won't check these details anyway. Both parties tend to revert to 2D PDF drawings to agree on details, and more importantly figure out whose fault it is in case of a mistake in production.
ECAD is way more standardized than MCAD for information sharing and version control, and at least has industry standard best practices. MCAD is still a wild west, with mostly proprietary tools used for version control (several thousand dollars per user per year) with no hope of interoperability. And each vendor that offers automated quoting uses a proprietary system, with a lot of manual inputs.
Granted, mechanical parts can be much more complex and it's easy to make unmanufacturable parts in MCAD, whereas ECAD is basically a stack of 2D layers. But still, as a mechanical engineer I am amazed at how easy it is to order a PCB or even an assembled PCB compared to ordering the simplest machined part.
All of that will probably be solved when an AI is released that generates code-based mechanical CAD models (supporting tolerance annotations per mechanical feature) based on text/voice input.
