Question
I am a wood products manufacturing student from Nova Scotia Community College in Nova Scotia, Canada. I have an assignment to do that justifies the purchase of a sliding tablesaw over a conventional tablesaw in regards to building kitchen cabinets. I have to know how long it takes to manufacture them using each saw as well as the productivity gains by the hour, week, month, and year. We're using a 2-3 year payback period as a standard. I'm really lost with this assignment and would appreciate any help I can get. This is for a "fictional" company so hard numbers don't matter, it can be anything.
Forum Responses
(Cabinetmaking Forum)
From contributor U:
There really is no comparison between the two other than a monetary difference. With a tablesaw you can cut from an existing straight edge, factory edges are anything but. With a slider you can make your own straight edge. Everything depends on that first cut. You then would rotate the part to make your second cut, assuming the factory edge is square if you use a tablesaw or with the slider you can get a square part from one that is not. Cost justifying between these is like getting to Hawaii in a row boat or on a cruise ship, they both will get you there. Which is more practicable?
As for your comparison we have a cabinet saw but it is never used for large panels. When we used to cut all our parts on the slider (pre-CNC) we averaged ten minutes per sheet on jobs ten sheets or more. Hopefully someone on here is cutting cabinets on a cabinet saw to give their times for you to compare.
In your report note some benefits of a sliding saw:
- Cut quality improved on sliding saw with scoring blade.
- Less operator fatigue, saw carries the weight.
Replacing a cabinet saw with a panel saw will only give a very small improvement. I'd say two or three minutes per cabinet - probably fewer. They take up a massive amount of space are necessary to be able to take advantage of other production improvements. The difference is a European shop (slider, bander, boring machine) vs. a traditional shop (cabinet saw, dados, glue and nails, manual or jig drilled hardware after assembly) is huge. If you are just talking about carcass production then it’s 1/3 or 1/8 of the time in many cases. The use of face frames, low grade plywood, and traditional types of hardware will throw a wrench into these numbers.
You should question your instructor on this assignment. Are you to factor in all the post cutting operations, or simply the cutting operation? If it’s just the cutting operation and you are comparing say a $3k cabinet saw and a $12k slider, I don’t think you would see a payback in two-three years. Now if you can apply a quantitative value to the quality of parts and how this benefits downstream processes right through to installation, you will realize a payback.
Also in the equation, a slider will not replace a cabinet saw for everything. You still need the cabinet saw. We went through a constant change as the business grew. From cabinet saw to slider, to CNC beam saw to a CNC router for detailing, to a big nested router. I can't say that I think any of them totally replaced the previous one except the change to the nested router. We are now considering/planning for how to increase efficiency as work increases. Material handling, CAD system improvements, and in machinery a small vertical router to handle roughed out parts from the CNC panel saw. The cost of the small router is about $80K. It has limited size capabilities but is fast, quick to load and unload.
The tradeoff, which is hard to measure in money: stack cutting on the saw is very fast vs. the time spent re-handling the parts. With little revamping of our panel processing area we can fit the small router in next to the saw outfeed conveyors and link via existing conveyors and transfer cars to the rest of the operations. This illustrates that not all machinery selection can be based on "payback time" since many of the considerations are very difficult to put a price on. Not that we don't try but the SWAG method has some limitations.
This is a great opportunity for you to impress your teacher by stressing the process over the operations. Operations are the individual steps required to produce your product, like cutting, planing, banding, drilling, clamping, assembly. The production process is a holistic view of the entire system.
Many business owners are not experienced enough to make process related decisions on upgrades to the production line. If they are not on the production line dealing with process first hand they tend to focus on the machines and their throughput. If there is a problem in assembly they will buy complex and very expensive systems to speed the glue drying (I am thinking of a wood welder for case work).
The better solution could possibly cost a lot less and improve the product. Switching to dowels, or using case connectors like confirmats would practically eliminate the clamp time and eliminate the need for several other processes like rabbiting the case and aligning the parts. This solution would never occur to the owner because he is focused on the operations not the process. Cutting panels is an operation and if it is considered on its own without the context of the entire process you are likely going to have a hard time improving the process.
