CNC Saw vs Sawjet for Cutting Stone

By Darren Mehr

According to the U.S. Bureau of Statistics, the unemployment rate in October was at 3.7 percent, which hasn’t been seen since the 1960s. We continuously hear from fabrication shops of the trouble they are having finding reliable, trainable workers, and so they are looking at taking advantage of technology to help ease the labor demand.

A variety of efficient technologies have been developed to improve any number of areas for stone fabrication businesses, from templating and installation to job management and inventory systems. Of course, the fabrication process itself has not been overlooked. Automation of the cutting process is a valid option for some companies to decrease their need for additional labor.

That leads to the question, what technology is right for a given fabricator?

As such, comparing a CNC saw to a sawjet can be helpful.

A saw blade is the most efficient and cost-effective tool for dimensioning hard surface countertops. This efficiency does come with limitations however. The roundness of a blade doesn’t allow it to cut an inside corner completely out, nor cut an oval sink or other similarly tight radius work. Utilizing a waterjet to cut stone is more expensive than a CNC saw blade, but it does allow you to complete the areas that a blade cannot. A sawjet combines both of these tools to achieve the efficiency of a blade with the flexibility of a waterjet. It will use the saw blade for any straight cuts it can, and only utilize the waterjet where the blade can’t reach.

CNC saws will cut the brunt of stone countertop materials in the neighborhood of 100 to160 inches per minute. These machines shine the brightest when dimensioning standard-sized, straight-lined shapes where it’s possible to line up the cuts like a grid.

For example, a lineup of nine 36-in. vanities placed three wide by three tall in a single slab would be an ideal setup for the CNC saw. A CNC saw is capable of having those parts dimensioned in less than 10 minutes. When operating a CNC saw with this type of work, it is safe to expect to fabricate around three to four slabs per hour. With production ramped up to three to four slabs per hour, the next step would be to figure out how to cut out 36 sinks in an hour to keep up with that rate of production.

A CNC saw is fully capable of other work as well, but this is where inefficiencies often appear. In a typical production environment, not all pieces are the same size nor do all the cuts line up. A CNC saw is fully capable of cutting those types of projects but it might require leaving more material in between pieces, or utilizing an operator or vacuum lift to move parts around mid-cycle.

 A move during mid-cycle increases cycle time and creates a potential accuracy issue if additional cuts are needed in the moved piece. When cutting out sinks with a CNC saw, multiple step cuts are required around the sink profile while using an incremental router bit. This adds an additional 15 minutes average per vanity sink. If you don’t have any other automated cutting solutions for sink cutouts, this can be a great option provided you don’t need the machine time for dimensioning parts. In many cases, these all may be acceptable CNC Saw vs Sawjet tradeoffs depending on your production needs and cost and quantity of material you’re using.

A sawjet marries the efficiencies of a CNC saw blade with the powerful waterjet, which minimizes the cuts that are hard to make using a blade on its own. The waterjet is capable of cutting 90 degree inside corners and any shaped sink a designer can dream up. The same vanity sink that will take 15 minutes on the CNC saw, will take less than 5 minutes with the waterjet. The waterjet will only be used if the blade is unable to easily execute a specific cut, utilizing the strengths of each cutting solution to the fullest.

Most stone fabrication shops have the same two items fill the cost buckets the quickest – material and labor. A CNC saw can surely decrease the labor portion, but when it comes to material, there will be little to no savings. However, a sawjet is capable of decreasing both of these costs.

It is difficult to calculate an exact increase in material utilization across the board because there are so many factors at play, but we’ve often heard from owners that their monthly material costs went down by 10 to 20 percent after introducing a sawjet into their production. This is mostly attributed to not having to worry about the overtravel of the blade when doing layouts, allowing for much tighter nests. A sawjet will also decrease labor because it has the ability to cut sinks and radius work in an efficient manner, in addition to producing more complete pieces to be passed on in the fabrication process. This will ease the workload on the fabrication process downstream.

Now there’s no question the initial financial investment of a sawjet will be greater than that of a CNC saw alone. In addition to the initial price, there are consumables related to waterjet cutting. The big question is, will the benefits of increased material utilization and decreased labor, offset these added costs.

Another factor that we often hear is that the additional expense of operating a sawjet is worth it because of the ease of setting a slab down, walking away and returning to a near-finished product all while gaining great material utilization.

Every stone fabrication business will run its operations differently according to its level of production needs. When considering which machine, CNC saw or sawjet, makes sense for your business, it is advised to make sure you understand the areas in which you need assistance.

A CNC saw is a great step in the direction of automating a shop. The questions to ask yourself include how big of a step is your shop ready to take and what are your shop’s plans for future growth. It is important to make sure that the sawing solution you choose to add to your shop will not pose restraints on future growth.

Stone can be cut with a CNC saw or a sawjet. When is the right time to use each method? Assess the needs of your shop and choose the solution that will provide the most benefit today and into the future, based on your calculations. The most value is gained when you are using the machine that is best suited for your shop.

About the Author

Darren Mehr is a Sales Application Engineer for Park Industries, a supplier of various machinery and equipment for the fabrication of stone. More information about Park Industries is available on its website at www.parkindustries.com.