CNC machining | Features

Smart Tool System (STS)

Homebuilders and stone fabricators are seeing a steady increase in consumer demand for more countertop profile options. The problem that this poses for stone fabricators is that when exchanging one set of tools for another, the wrong set of tools can be placed and tool information may not be updated properly. The results of such mistakes are costly--damaged tools, damaged stone, and/or machine down time.

The Northwood 138-EDS and 158-EDS are equipped with standard 30-position tool storage racks which provide the fabricator with storage space for four complete standard tool profiles (bullnose, ogee, pencil edge, or seam) as well as finger bits, core bits, a calibrating wheel, and a Z50 wheel. In response to the increased demand for more profiles, Northwood Machine Manufacturing Company developed an innovative solution for stone fabricators. The optional Smart Tool System (STS) is a modular, automatic tool carousel and software program that provides a scalable, autonomous system for the storage and delivery of tools to a machine tool spindle on a Northwood CNC machine tool or router.

With STS, Northwood’s stone routers offer:

• infinite tools and profile set options
• quick and simple tool changes and job setups
• secure and efficient storage of tooling investments
• reduced chances of crashing the machine when swapping tools during processing
• no errors with cutting the wrong edge onto a countertop

The STS system includes detachable racks or carousels that can be stored offline in a stand or cart; with each rack representing a tool profile set and containing an automatic means for home tool position recognition and automatic profile set identification. STS provides offline tool setup and reduces the need for tool storage space at the machine. STS also provides a substantially increased number of tool positions over traditional rack or chain systems because an unlimited number of profiles are possible per machining cycle with STS!

In addition to the multiple mechanical advantages, the STS system also includes powerful software that provides automatic storage and retrieval of tool set information and displays individual tool and/or tool set parameters relative to the corresponding carousel or rack. STS offers seamless integration with tool measurement means and/or digitizing for tool identification, drawing, adjusting for wear and/or matching tool profile geometries, and for automatically applying various operational parameters.

Ergonomics

Northwood designed these machines with ergonomics in mind. When the machine completes a program, the massive machine gantry retracts to the rear of the machine providing total access to the machine's worktable. This provides the necessary clearances for material lifting equipment as well as a clear view for the StoneLaser™ pod/part location system. Even the water collection tank in the front was designed to serve as a step to provide easier access for the machine operator for loading and unloading the machine. In addition, Northwood’s revolutionary StoneScan™ barcode data input system is seamlessly integrated into the machine's GE Fanuc control.

The machine's computer-designed frame structure is so rigid that the entire machine can be lifted by a single (large) forklift and positioned in the shop. The massiveness of the Northwood NW-158EDS and the 138EDS (Gen4) prohibits it from fitting into a shipping container, which is the reason it is available only in the U.S.

StoneLaser™

The traditional approach to CNC stone machining has consisted of a very archaic and time-consuming process using the machine tool to position part locator pins, vacuum pods, and parts. The problem with this method is that it halts production because the machine cannot produce while being set up.

Northwood engineers attacked this industry problem and developed the revolutionary StoneLaser™ system, which automatically projects the layout pattern across the entire work table. The machine operator simply positions the Blick vacuum pods and aligns the blank material with the part geometry that is automatically projected by the StoneLaser™.

StoneLaser™ reduces set-up times so much that up to 30% more countertops can be produced per shift on the same machine. The outcome is very simple - Northwood CNC stone machining centers produce more countertops per shift than the competitors' do.

SuperZ™ Technology

The Feedrate Barrier is Broken

The general consensus in the industry has been that increasing productivity with higher machine feedrates was not feasible until a material harder than diamond was discovered. In fact, Northwood subscribed to that philosophy and focused on developing improvements in machine set-up efficiencies to increase output from the machine. This led to the creation of the revolutionary technologies of StoneLaser™, StoneScan™, and the LTC System. All focused on making the machine set-up much faster, and thereby increasing machine productivity (up to 30% more at the end of the day).

The strong torque characteristics and overall strength of the Extreme Duty Spindle (EDS) have yielded an unexpected benefit--they have facilitated the development of SuperZ™ Technology. Imagine getting an additional hour of machine production per shift because of faster machining!

Now it Makes Sense to Machine Wall Scribes

Machining wall scribes has always been an option with CNC technology, but the machine time required to do it has made it prohibitive. It takes too long with a finger bit, and saws do not cut curves very well. SuperZ™ technology allows you to machine an eight-foot wall scribe in as little as one minute. If you use an electronic template method, simply digitize the back wall and machine the digitized edge to create a countertop that fits the wall perfectly with no sheetrock modifications required.

Very High Feedrates

With SuperZ™ technology, the finger bit is now used simply for rounding off radiused corners, sink cut-outs, etc. The majority of the work normally completed (very slowly) by the finger bit is now performed with SuperZ™ technology, at feedrates as fast as 100 inches per minute. The end result is finger bit usage that is roughly 10% of what it was previously. In addition, the finger bit is being replaced with feedrates up to eight times faster! As a result, Northwood users are picking up as much as one extra production hour per shift.

C-Axis Saws Have Become Obsolete Technology

The major justification for C-axis aggregate saws on the stone CNC has always been to reduce finger bit usage (and cost). Although the saw feedrates in the material are much better than with the finger bit, the additional time required for head positioning, etc. make sawing only slightly faster than the finger bit. SuperZ™ technology provides the reduction of finger bit usage enjoyed by saws with machining times that leave the saw standing in the (stone) dust!

Warning! SuperZ Technology Can Damage Your Electrospindle!

Use SuperZ™ technology with your electospindle at your own risk. The EDS develops its power at low RPMs because the motor windings have been designed to produce very high torque at the RPM ranges customarily used to machine granite. In fact, the spindle could be used for rigid tapping in steel!

Electrospindles for stone were derived from the glass industry, where higher RPMs are required. As the spindle RPM's drop to the levels needed to machine granite, the power output from the electrospindles drops off significantly. As long as you are machining a homogenous granite (or engineered stone) material, feedrates can be adjusted to control electrospindle loads to achieve acceptable feedrates. The problem occurs when you try to machine granite materials with inconsistent densities utilizing SuperZ™ technology on an electrospindle. The electrospindle can bog down before the operator can take corrective action, and permanent damage the electrospindle can result.

Because the EDS was based on machine tool technology, it has the ability to provide very high torque levels at low RPMs so encountering hard spots with the SuperZ™ technology has little impact on the spindle.

Laser Tool Calibration System (LTC)

Tool Wear Leads to Development of LTC System:

Naturally occurring variability in stone material makes it difficult to maintain the ideal tool relationships for any extended period. The idea tool set-up is temporary and once changes start, tool tweaking results in wasted machine time. Northwood developed a technology that periodically allows the machine to accurately measure each tool and automatically make adjustments in the machine’s control for material variability and tool wear variability. Northwood’s revolutionary LTC System employs a very accurate laser beam to measure tool diameter dynamically. This provides a measurement repeatability of +/- 0.0002” (or less) and totally eliminates the measurement problems associated with water droplets.

Operational Simplicity

Northwood’s StoneScan barcode data input system controls the entire process. The machine operator simply scans a barcode and the machine picks up the correct tool, dynamically measures the tool’s diameter, calculates the actual tool wear, and updates the machine control automatically. When the process is complete, the relationships between each of the tools is then the same as when the perfect set-up was established!

Consumption Tools

Some tools wear at a much faster rate than others and require a slightly different tool strategy to keep that perfect set-up. Both finger bits and resin polishers (clay) wheels require such strategies.

Resin Polishers: The LTC System measures the tool and updates the machine control so that the exact amount the tool has worn is compensated for – no more, no less. This process eliminates the inaccuracies in polisher wear that accumulate as the polisher is used repeatedly. Ultimately, significantly longer resin polisher life is achieved.

Finger Bits: Finger bits produce a different consumption circumstance because of the impact the actual tool wear has on each tool in the profile set. Each of the abrasive wheels in the set has a specific depth of cut that is recommended . Finger bits wear at a much faster rate than segmented wheels. As the finger bits wear, the amount of material left for the segmented wheels to remove increases, which has an impact on each succeeding diamond wheel. The LTC System overcomes this problem by laser calibrating the finger bit each time it is placed in the tool changes. This keeps the differential minimum for the segmented wheel always within the tooling manufacturer’s specification. Great edge finishes and long tool life are the results.