Older manual machines were built to last; ”good bones” as they say. But as technology improves and the bar gets higher, manual machines may need a digital retrofit to be fully usable. That’s where digital readouts (DROs) come in; in conjunction with digital controls, they can essentially turn machines from manual to CNC with easy-to-use, digital functionality. Not only do DROs allow shops and training facilities to get more life from their manual machines, but they can improve productivity and raise the quality of the machined workpiece.
How DROs work
Put simply, a DRO is a communication device between the operator and the machine tool. The DRO displays the machine table’s direction, distance and location. The readout/interface itself pairs with feedback devices installed directly on the motion axes to provide positional feedback; operators can then see the position of the tool/workpiece on the DRO screen.
Common types of digital readout (DRO) systems
DROs can be used for a fairly wide range of machining applications:
- Milling (vertical boring mills, universal horizontal/vertical mills)
- Turning (horizontal lathes, vertical lathes)
- Surface grinders
- Optical comparators
- EDM machines
Common types of DROs range from entry-level DROs that provide measurement for a single-axis machine all the way up to advanced DROs with programming function capabilities and measurement of up to six axes. New technology is even making it possible to turn an ordinary iPad into a digital readout with a single app.
Factors to consider when purchasing a DRO
At the most basic level, all DROs enable the same thing: feedback to the operator about the position of the machine and workpiece to enable more accurate and productive machining. But choosing the right DRO for your specific needs involves a few key factors.
First and foremost, your DRO selection will depend on your machining application and type of machine, because different DROs support different machining operations and different numbers of axes. This simple DRO selector tool can help you make your selection based on machining application and number of axes. For those looking for one DRO for multiple machine types and applications, the new droPWR turns any iPad into a digital readout. It allows users to dynamically switch between milling, turning and grinding, with multiple configurations on one tablet.
In addition to basic considerations like type of machine and number of axes, you’ll also want to consider how much functionality you need. For example, different models of DROs might accommodate the same applications and axes number, but have different capabilities in terms of storing tool offsets and multi-step programs; enabling machining of more complex shapes; and delivering presetting capabilities. Some advanced models allow users to measure, create, construct and export 2D feature types, including point, skew, line, distance, circle and angle. Get a quick comparison of several of these models here.
If the digital readout console is the face of your DRO system, the feedback systems are the brains. These feedback systems generally come in three types: glass, inductive and magnetic. The choice you make will depend on a few factors. For example:
- Glass scales, which read changes in light to make measurements, are extremely accurate and precise.
- Inductive encoders detect changes in capacitance reactance and translate them into motion measurements. However, they usually require more mounting space and aren’t highly accurate.
- Finally, magnetic encoders scan alternating magnetic poles as the machine moves and detect changes in magnetic flux fields. They’re slightly more accurate than inductive encoders, with smaller footprints, but can be susceptible to extreme temperatures.
Ease of use
Ease of use can be a big factor for a typical DRO user—either those training operators to use new technology; those bringing on less experienced operators; or instructors teaching students to use machinery for the first time. Like most technologies, ease of use typically correlates with the sophistication of the technology. More entry-level DROs have fewer bells and whistles, but a lower learning curve for simple machining tasks. More feature-filled DROs offer greater benefits for more complex applications, but may require a bit more training/education. In general, however, today’s leading DRO manufacturers are committed to making DRO systems that are both intuitive and robust.
As with ease of use, your needs will influence the amount you should plan to spend on a DRO system: the more demanding the application, the higher potential cost. And, as with most things in life, you usually get what you pay for. One thing to keep in mind when justifying your investment is the cost of swapping out a manual machine entirely—versus the cost of retrofitting it with a high-quality DRO system.
Factor to consider to choose the best DRO brand
Once you’ve narrowed down your needs for a DRO, you may find yourself comparing similar models from different brands. How can you know which is the right choice? Use this list to determine how different manufacturers measure up.
Brand reputation and track record
In a day and age when you can buy tooling (and yes, DROs!) on Amazon, it pays to do some research on the brand and provider to ensure the manufacturer has a proven track record of product quality and support. For almost 60 years, ACU-RITE DROs have been made in America, in an ISO facility. Perhaps most importantly, ACU-RITE is a member of the HEIDENHAIN Family of Companies; HEIDENHAIN is a known world leader in precision feedback and motion control—one of the most crucial success factors for a DRO system. The manufacturer you choose should have case studies and customer testimonials to back up product and support claims.
Quality, accuracy and durability
As mentioned, a DRO is only as good as the feedback system that drives it. This precision feedback function has been ACU-RITE parent company HEIDENHAIN’s bread and butter for 130 years (you read that right!). Whether you need a system that will endure the harshest industrial conditions or will deliver the utmost in accuracy (or a little of both), HEIDENHAIN and ACU-RITE have a wide range of options to choose from. When it comes to the DRO console itself, you’ll want to make sure the IP rating and overall construction stands up to your shop conditions (moisture, temperature, contaminants, vibration, etc.).
Before you choose a DRO brand, you’ll need to have a handle on installation requirements. Some systems are off the shelf, and will require manual adjustments on the user’s end to make hardware fit and work properly (adjusting scale mounting brackets, for example). ACU-RITE is the only manufacturer to offer custom mounting kits suited to your specific machine model (with over 100 different machine make and model options)—to make installation much faster and eliminate human error.
Your DRO brand of choice should have a DRO option that fits your needs perfectly—from the feedback system and console to the installation kit. This will ensure not only that the system works exactly as it should, but also that you won’t have any hiccups when it comes to installation. ACU-RITE offers a wide range of DRO system options, plus custom mounting kits for more than 100 machine makes and models for foolproof retrofitting.
Service, support and warranty
Last but certainly not least, does your DRO brand offer solid service and support? If they aren’t in the United States or if DROs are not a main focus for them, the answer may be “no.” America-based ACU-RITE provides easily accessible support by phone, appointment or online. What’s more, every ACU-RITE DRO has sophisticated help functions built in. With the press of a button, users can access help and step-by-step installation/retrofit instructions. Finally, all ACU-RITE products come with a two-year warranty.
Even armed with all this information, it helps to talk to an expert when making a decision on which DRO is best for your operations. Call 1-847-490-1191 or contact the ACU-RITE pros online for a free consultation and quote.