Is there any way to determine about how long a CNC project will take? I’m mainly curious about the actual routing time, without computer work and finishing time. I know there are many variables. I recently watched on YouTube “Making Signs with a CNC Router.” This was a very good video for a novice. I would like to know how long it took on the router itself.” – Michael Byars
Chris Marshall: You’re right, Michael, in suggesting that there are a lot of variables here. The amount of routing time will vary, project by project, depending on its size and complexity. Deeper or wider passes will require the router to go over the same area multiple times, “through cuts” will take longer than simple edge-profiling, and so forth. In a sense, estimating the routing time for CNC is like estimating the amount of handheld routing to, say, make a sign, mill a cabinet door or dovetail a bunch of drawers. It’s a pretty hard factor to quantify. But, one thing will be true: once the programming is worked out and the workpiece is prepared for the CNC machine, it will be faster for the CNC to complete most jobs than it would be to steer the router by hand.
Rob Johnstone: Good question, Michael. Once you have your sign programmed into the CNC and converted into what is called G-code, the dashboard will tell you how long the program will take to run. As Chris pointed out, there are several variables to consider, but within the program there is a control that lets you tell the CNC router how fast to cut per inch — within set parameters, of course. And this is where the human factor comes into play. You can tell the machine to cut too deep and too fast for the task at hand, and the machine will attempt it. The results will be bad — a broken router bit, poorly cut wood, the blank being torn free of its clamps — because, as Scotty from Star Trek was fond of saying, “you can’t change the laws of physics.” So, you will be able to know how long a sign takes to make, both from data on the machine, and after a bit of time making signs, but estimating from experience.
Tim Inman: So, how long is a piece of string? Way too many variables for an answer here.