I study machine tools for a living. I read brochures, talk to product specialist, follow technology trends in design and construction. New machine tool models and new series of models are introduced constantly. Sometimes “new,” just means a new model name without much, if any meaningful change to the product itself. On the other hand, with little or no fanfare and without even changing the name, some builders make sweeping changes to existing models. So it’s important to read the fine print, talk to your salesman, and understand what’s under the hood so you’ll know what you’re getting before you buy.
Quality builders never stop enhancing and improving the machine tools they make. Of course, new models that fill a size, function, or application gap are usually obvious. But quality builders are regularly known to ship the next unit off the production line with a better control, bearings, heat displacement device, way construction, or some other improvement that you may not be aware of or appreciate.
The Doosan DNM Series may be just such an example. The latest models being shipped use the roman numeral “II” as a subtle clue that something’s changed. The key specifications for travel, rapid rates, horse power, spindle and table size, are the same. But beyond the specs you’ll find important design and construction changes in the DNM 400 II, DNM 500 II, and DNM 650 II.
These models are now available with belt-driven or direct-coupled spindles. The direct-coupled design provides higher torque and cutting capacity while reducing noise and vibration. In the most critical aerospace applications in titanium, for instance, the direct-coupled spindle may not only be helpful, but necessary. Another change to look for in the DNM “II” series is the transition from ball-type way guides to roller-type LM guides which provide more bearing surface contact to withstand load and improve rigidity and extend wear. This is another new feature that will facilitate more productive and efficient machining of difficult materials without having to sacrifice optimal cutting tool feeds and speeds. An operator-appreciated upgrade is the redesign of the control panel which is easier to use and access during set up and production. Don’t underestimate the productivity gains that can be realized through even the smallest ergonomic enhancement. Though the BIG Plus spindle was used on the previous DNM series, some things just can’t be improved on, so Big Plus is still the spindle of choice. See my previous article on Big Plus and how it compares to other spindle designs. Other enhancements like the spindle cooling and thermal displacement systems further aid in machine stabilization even under the most difficult conditions.
You can’t tell if a machine has the latest technology by its model name. Stick with quality machine tool builders and ask a lot of questions to make sure the machine you buy includes technology enhancements that make a difference for your applications.