Fabricators and machinists of a certain age still remember the days when manual milling machines were prevalent in machine shops. These relatively versatile milling machines used end mills, face mills and other types of cutters to perform various milling operations using an x-axis table feed. A movable quill in the Z-axis instantly transformed these knee-milling machines into a drilling machine that could also tap, broach and even press bushings as needed. And accurate hole positioning was improved with a digital readout (DRO).
Today, CNC machines are the pride and joy of the shop owner, and the manual milling machine is usually limited to secondary operations and minor repairs. And the manual machinist has been replaced by a computer-savvy CNC operator who can guide a CNC milling machine (or even a CNC lathe) to do things that were unimaginable just a few decades ago.
Although the CNC machinist and the manual machinist are well trained and developing valuable skills, the machinist with skills on a Bridgeport-type manual milling machine will have different skills than the CNC machinist working with sophisticated machine tools and software.
Is the manual milling machine in danger of extinction?
The Bridgeport knee mill is alive and well, and even with the proliferation of CNC machine tools, you’re likely to see a manual milling machine somewhere in a typical shop. Most likely, it has an electric feed, a digital readout, a collet frame and a vise attached to the work table.
The manual knee router remains popular for small jobs that require a quick setup and a few holes in the workpiece. In addition, because the head swivels, the ram moves and the turret rotates, the manual router offers the flexibility for jobs that require a short machining time or do not lend themselves to programming a CNC machine.
CNC milling machines have advantages over conventional milling machines
Although both can perform vertical machining operations, one of the main differences between CNC and manual milling machines is the number of employees required. CNC milling requires only a few operations, and a trained CNC machinist can operate multiple machines simultaneously, while a manual milling machine typically requires only one operator. Reducing labor costs is the key benefit of CNC milling, but not the only one.
Once a CNC machine tool is programmed, its movement is controlled by a computer and it will repeatedly produce parts that meet the most accurate specifications. With manual machines, it is difficult to achieve consistent results because there is one critical factor: human error. That’s why there are quality issues in many shops that rely solely on manual milling machines.
When it comes to production, CNC machining wins the competition hands down. A CNC machine tool can produce thousands of parts relatively quickly, all of which are identical and meet specified tolerances. Higher spindle speeds, faster table feeds, automatic tool changers and, on some CNC milling machines, box paths can increase production that manual milling machines cannot.
Because machining the next part on a CNC milling machine usually requires reprogramming, changing inserts on the cutters and adding coolant, it can be quickly switched from one part to another. Complicated setups, fixtures and gauges are not required, saving tooling costs and allowing the prototype to be completed much faster.
Although CNC machining centers run much faster and produce parts in less time, they are safer than Bridgeport-type milling machines. CNC milling usually takes place behind a protective grille or closed transparent door, reducing the risk of injury. Workers have virtually no chance of getting their hands near the moving cutting tools.
Find a milling machine that combines the best features of manual and CNC milling
The CNC Supra Vertical Knee Mill features a vertical spindle and combines the advantages of a manual milling machine with the many benefits of a high-performance CNC milling machine in an excellent and versatile combination machine tool that can produce one-offs and small batches as well as mass-produce replacement parts. Many of the jobs that can be done quickly on the CNC Supra are virtually impossible on a manual milling machine – at least not without using expensive and cumbersome fixtures and tooling.
Depending on the type of work, the Supra vertical milling machine can run for hours without an operator, or only for part changes during shorter runs. The X-axis, Y-axis and quill-driven Z-axis can move simultaneously for three-dimensional work, driven by microstepping motors, while the computer controls the variable-speed head.
Still, the CNC Supra can also be controlled manually when the other CNC routers are underutilized. Perhaps the traditional manual router has died out in the shops that use the CNC Supra vertical milling machines.
Do you need a CNC milling machine with a smaller footprint?
Even though the CNC Supra vertical milling machine takes up much less space than other machine tools, your situation may require a more compact CNC milling machine. In this case, the CNC Max benchtop router is the solution to your dilemma. The MAX offers considerable travel: 21.5″ on the X-axis, 10.5″ on the Y-axis and 4.5″ on the Z-axis quill. And all three axes are equipped with ball screws to ensure accuracy during production.
But don’t underestimate the MAX CNC router just because it’s a tabletop machine. The MAX is a rugged and precise vertical router with a cast-iron housing that performs as well as larger routers without taking up as much space. It is built and hand-tested for quality and performance in California, USA, and is suitable for primary or secondary CNC machining applications.
Manual milling machines vs. CNC milling machines: a conclusion
As you already know, comparisons are only valid if you are “comparing apples to apples,” as the saying goes. If that’s the case, it might be unfair to compare manual to CNC machines. After all, CNC machines have so many advantages that they have turned manual milling machines into dinosaurs.
Although CNC milling offers a great advantage over traditional milling machines in that it saves on expensive labor, ensures quality and repeatability, can handle complex three-dimensional work, and is versatile, the manual milling machine still has its place and purpose in many businesses. Startups may opt for a less expensive manual machine, and those without computer skills may forgo a CNC router, at least temporarily. And if your company has several large projects going on, it’s good to have a manual milling machine on hand for small emergencies.