Machined parts and pieces surround each of us every day, yet rarely do we stop to consider the process that goes into their creation. Since Krownlab sliding barn door systems contain a number of machined parts, we thought it would be interesting to sit down with one of our engineers and discuss the basics of the CNC machining process.
What are the benefits of a CNC machined parts versus being simply cast?
Castings only provide the rough geometry of parts. The main advantage of casting is that solid, complex shapes can be formed in a single step eliminating wasted material that would otherwise be carved away in machining steps. Any finished surfaces however, such as holes, threads need to be done by skilled people as secondary operations. This means more processes, equipment, touch points, time, logistics etc. Casting is also a relatively inexact science meaning that defects are more commonplace. The process requires expensive molds that typically need to be scrapped and remade if there is a design change to the part. Not to mention, casting vendors aren’t on every corner. By strategically designing parts that are suitable to be CNC’ed, we can get parts that are very precise and require few if any secondary operations. Since the only thing needed to make the parts is a CNC and a CAD file, just about any shop can make them. Also, if the part changes slightly, CAD simply gets updated; no new molds required. When it comes to material, choices become endless and more optimal alloys can be specified. The trick is to design parts that can be made out of standard shapes like bars and sheets with minimal material removal for efficiency.
For Krownlab sliding barn door hardware, how many different machining processes are used (not just CNC)?
Let’s see, we have parts that are: CNC, laser cut, drilled, sawed, ground, turned, linished, broached, etched, polished, pickled, tapped, planed, honed, tumbled…. Probably around 20 or so different machining processes. That’s just machining (subtractive); there are probably another dozen or so additive processes such as coating, oiling, painting etc.
Do you think 3D printing technology will eventually replace CNC machining?
I don’t believe that 3D printing will ever replace machining simply because on a cellular level, the material just isn’t the same. Material that has been worked, forged and rolled like sheet, bars etc have strength advantages from the aligning of molecules. However, I do feel that more and more, we will see parts with minimal strength requirements start to be printed. We are already doing this ourselves to some extent. Another place that 3D printing is gaining advantage is with exotic and hard to machine materials. For example, the tailpipe on the Koenigsegg One:1 was designed to be made of titanium but machining that much Ti just isn’t practical so it is printed instead.
In our searching, we've come across a number of really great sources for further information on CNC and other machining processes. Knowing how the objects around us are created can help us make better, more informed decisions on how we use them!
photo credits: 3dprint.com, Qualiturn-cnc.com, partnersmfg.com