When considering the best practices of using a CAM system to program CNC equipment, some really important factors about the CAM system itself are key to getting the most return on your investment. These factors usually fall into two categories: Time and Direct Cost.
- Programming Time – how long it takes a programmer to create a tool path for a part.
- Cycle Time – how long it takes each part to come off the machine.
- Rework Time – will the part have to be worked on by hand (sanding, deburring, hole drilling, etc.) to meet a dimensional tolerance or surface finish?
- Scrap – how many parts will be unusable, costing both time and materials.
- Tools – How many cutting tools will be required to finish the job?
- How much maintenance will the CNC machine require?
What many people may not realize is that choosing the right CAM system has direct impact on all the factors mentioned above and they all directly impact profitability. The good news is that a new generation of CAM systems has reached remarkable levels of power in terms of enhancing profitability. Nearly 100 percent% of this power comes directly from two features of advanced CAM programming systems: Integration with CAD and Intelligent Tool Paths.
Integration with CAD:
Over the last several decades, computer assistance in manufacturing has grown and evolved from simply computerizing the 2D “Drawing” of a component or assembly of components, to really “Modeling” the physical presence of the mechanical design. This opened the door for CAM programming to be able to use design data directly from the CAD design file. However, the old process of importing a design file into a separate CAM programming system often caused data loss issues, resulting in the need to identify and rebuild lost components. Even more , restarting the entire programming process from scratch if/when revisions required the design file to change. The need to learn and maintain two distinctly different products for CAD and CAM.
The best CAM systems are now directly integrated within the CAD environment, where they actually run inside the host CAD system to bring CAM programming operations directly to the design model. Not only does this eliminate design data loss from file export/import, it provides a familiar and singular environment where designers and manufactures communicate their needs with a common platform. No longer are designs “thrown over the wall” to the machine shop, with no opportunity for the machinists to have crucial input to the design model. This added flow of communication ensures designs truly take manufacturability into account, saving huge dollars in wasted efforts, scrap and machine downtime.
The other major benefit is that CAD design changes (made so easy by parametric modeling – change a dimension, and the entire model updates), now flow directly to the CNC machine, as tool paths automatically are updated as well. What used to make a CNC programmer have to completely start over, is now a single keystroke to “Update the tool path”.
Intelligent Tool Paths:
With a traditional fixed “step-over” tool path, the cutting tool goes through material as though it were on a racetrack, “stepping over” a fixed amount to cut the next row of material (See figure one).
This creates areas where the tool is subjected to heavy forces, especially in tight corners. For years, CNC operators had to slow down the cutting operations and take very shallow cuts to minimize cutting tool breakage and wear in these cutting tool high stress areas from these damaging forces. To make matters worse, the slow speed of the cut and the shallow depth of the cutter, are set for the entire process. So throughout the entire cut, the impact of even just a few problematic areas could severely slow the entire process down and cause high rates of tool wear. This also greatly lessens cutter life as only a small percentage of the bottom of the cutter is used during shallow cuts.
An Intelligent Tool Path has several benefits over the traditional tool path, as it takes into account Cutting Tool Parameters, Material Parameters and Machine Parameters in such a way as to minimize the forces that result as the tool travels through the material. First, advanced intelligent tool paths manage the cutting angle (See figure two). When the cutting angle is properly controlled throughout the entire cut, the result minimizes the forces on the tool, allowing the tool to cut much deeper without excessive wear or breakage. Deeper cuts, using all of the cutting tool length, require far fewer passes, greatly reducing the cycle time of the part. Also, since the entire cutting tool length is used, tools are no longer replaced with only a small percentage of the bottom of the cutting tool used. Cutting Tool life dramatically increases to many times that of a cutting tool used in a Traditional tool path. Another major benefit is the ability to use small cutting tools, even for really hard materials to bid more jobs, all without buying extra equipment.
Second, top level Intelligent Tool Paths manage the “Feed Rate” which is the speed that the cutting tool is travelling as it moves laterally across the part. Most systems use a fixed “Chip Load” to set the “Feed Rate”. Chip Load is measured as the distance moved per tooth, per revolution of the tool. A better practice, used in the most advanced Intelligent Tool Paths, is to analyze the motion of the tool relative to the cutting angle and through sophisticated algorithms, adjust the feed rate in a manner that keeps a constant Chip Thickness as it is measured at the actual Cutting Angle. This reduces or eliminates the uneven loading and unloading forces on the tool that significantly reduce the life of the Cutting Tool. By having a constant and reduced load on the tool, tool life is greatly increased. See Figure three.
Third, Intelligent Tool Paths manage cutting tool repositioning. With Traditional tool paths, the cutting tool is often raised back to a starting point for each repositioning to the next cut entry location. Advanced Intelligent Tool Paths analyze the material already removed, calculating the shortest path for the “reposition move” and determine how to keep the cutting tool in contact with the material for as long as possible through the entire cut. Unnecessary moves and “cutting air” are eliminated, resulting in seriously faster cycle times.
One last benefit of Intelligent Tool Paths is that with all the cutting tool control, the most advanced CAM systems have parameter wizards (See figure four) that automatically take the guess work out of setting how fast your CNC machine should spin the Cutting tool, adjust the step-overs and how deep to cut. For decades, CNC operators have used “tried and true” settings stored in reference books or passed down in from other machinists. Since Intelligent Tool Paths are so much more efficient, these settings are no longer even close to what should be used. This makes a Parameter Setting Wizard critical for truly optimized cutting and maximum profitability. These Wizards also end countless hours of trial and error and as well as sacrificed stock material if a CNC operator had to find the best settings on their own.
If you do want to maximize your profitability and you start looking for the most affordable and powerful integrated CAM program with all the features mentioned above, SolidCAM with iMachining, is a good place to start. The best integration to SOLIDWORKS, the best support (made up of 100% factory trained machinists), the most intelligent tool paths and the only one with the iMachining wizard for effortless optimization. So when you combine the time savings of Integrated CAM with the benefits of Intelligent Tool Paths, the impact on your profitability is deeply dependent on finding the best CAM system.