From Ben TerreBlanche, SigmaTEK President & CEO
The CAD/CAM Decision for CNC Manufacturing
CNC Machine Manufacturers face a dilemma when it comes to opening up CNC control architecture, which is required for flexibility and possibility to integrate with other systems in a company, versus compromising cutting technology innovation and intellectual property.
For example, what is the best approach for cutting ¾” stainless on a 5000W CO2 laser with nitrogen when the geometry is intricate? Laser cutting machine manufacturers do not have consensus on this. Each laser OEM has unique details of how to balance the trade-offs of quality, cycle time and process reliability to best position their solution in the marketplace. Whether it is special treatment of the pierce point and lead-in, exact stops in corners, feedrate ramping, laser power ramping, etc., or all of the above – each manufacturer’s solution amounts to intellectual property worthy of protection.
Another example is the detail of the process of a press brake operation. Dealing with the cycle time, handling work load for the operator, part quality, tooling optimization and tooling compensation, again, are functions uniquely solved by press brake manufacturers.
Adding Variables to the CAD/CAM Decision
Even with tube laser cutting machines, the same challenges exist. The cutting technology to deal with cutting the knuckle on square tubing or the multiple cuts required to process an open channel section is approached in unique ways by machine builders.
This dilemma is not limited to cutting machines. Similar issues exist in plasma cutting. Cutting a “bolt hole quality” opening relies on detailed manipulation of torch height, cutting feed rate, power supply shut-off procedure and timing, combined with the shape of the cutting contour lead-in, among other variables. By balancing these variables, normally using empirical techniques, the resulting “recipes” from different plasma machine and plasma power supply manufacturers are unique.
Plasma machine bevel cutting adds yet another set of variables to the equation, which is the five-axis motion required to cut weld preps and chamfers during the cutting of the nesting layout. Some of the challenges facing machine builders are height sensing; how to handle corners, with or without corner loops; blind bevels with rapid head tilt transition or the more conservative new pierce point method; and plasma flame torch taper compensation.
The Importance of Choosing the Right CAD/CAM Software
There are three ways machine builders can overcome this dilemma. First is to open up the system completely, leaving it to the end user and/or the CAD/CAM software system to provide the detailed process variables to make the cutting machine perform. Whereas this allows the potential to integrate, the disadvantage is the machine might end up under-performing if the CAD/CAM software is weak on process detail. Also, calibrating cut quality will be time consuming for the equipment’s end user.
The second approach is to completely shut the system down with programming language encryption and/or binary technology information. This will allow some part of the unique and sensitive technology to be protected but it causes severe frustration for experienced customers with system integration requirements. Machine OEMs often take advantage of this opportunity to supply bundled proprietary CAD/CAM software. This practice amounts to forcing the customer’s hand instead of allowing the proprietary CAD/CAM software to be selected from within the range of solutions on the market. Whereas this approach may be acceptable to first-time machine buyers, customers will want to “jail break” eventually and that could put the reputation of machine suppliers following this approach in jeopardy.
The Best CAD/CAM System: Versatility PLUS Cutting Excellence
The third, and in my opinion the best, approach is to provide an open and fully functional NC programming language (ISO or G-code) with macro functions, technology database tables and sub-routines accessible through the programming language that will make the machine perform in an optimal and predictable way as far as process detail is concerned. This will not only protect key intellectual property but will allow scalability and potential for integration. Furthermore this will afford the marketplace with the freedom to select the most suitable CAD/CAM system for a particular application rather than to be coerced into using a possibly inferior or for whatever reason less suitable system.
Companies purchasing cutting machines should not allow the CAD/CAM software part of the conversation to be trivialized. Software is the brain that drives the machine directly impacting performance, productivity, material savings, and ROI. Such a purchase should be given every bit of consideration, analysis and scrutiny as any capital investment.