One of the oldest automation tools that found its way into the signshop is the CNC router. That may sound odd, but the technology behind a router is basically the same as a vinyl cutter. A tool holder is moved in a XY-coordinate system using motors and encoders in order to provide precise positioning. An additional Z-axis allows for the tool to be raised and lowered. All of this is driven by a software controller that will take some form of artwork as input and convert it to tool positioning at the table. This sounds really easy, so why is there such a wide difference in pricing when you are shopping for a CNC router?
First off, how do you intend to use the machine? For signmakers, there are a number of useful functions that a CNC router can perform. The simplest purpose is probably cutting out sign blanks. Sure, you can do that with a table saw if the blank is rectangular or square. But how about a blank shaped like the state of Texas? A very skilled person with a jigsaw could probably do it, but who has that skill today? A router can also create relief-carved signs. These babies can make some real money. Again, a skilled carver can do incredible work. Do you have one on staff? A CNC router can perform numerous other tasks without the need for highly skilled craftspeople. The questions then become, what is your budget, and what features do you absolutely need?
TABLE SIZES AND MORE
A good first question to ask is what size material do you need to handle. In most cases, a 4 x 8-ft. capacity table is a perfect choice. Most raw materials such as sign foam and MDF come in 4 x 8-ft. sheets. If you don’t believe you will ever need that size, then a 4 x 4-ft. table may be suitable, and you can save a few bucks. On the other hand, larger-capacity tables will cost you more but they are definitely available. Speaking of materials, you also need to determine what type of hold-down system you want for the material. Lower-cost routers use clamps instead of vacuum zones. If you are working with heavier materials, this will work fine. But when you work with thinner materials and finer parts, the clamps will not hold them in place after the through-cut is finished. A vacuum table will make sure nothing moves until the job is completed.
Production schedule is another factor in deciding on a router. If you are only using the machine a few times a day, then speed may not be an issue. Like cars, speed costs money when buying a CNC router. If your goal is to crank out pieces in a shift, then you want to reduce operator intervention as much as possible. In some cases, the operator may need to change the tool from one bit to another during a job. This can take time and means the router must pause. Many routers have an option for automatic tool changers that will perform this task without operator intervention. On a final production note, the power of the spindle (router head) can affect performance. For example, it may take multiple passes for a low-powered router to cut through a 3/4-in.-thick board. A higher-powered head will be able to accomplish the cut in a single pass.
A couple of final notes on choosing a CNC router: If your budget is very small, you may want to consider a handheld CNC router. These devices are placed onto the material and will route a section. An index guide is used to move to the next section to continue the job. Obviously, this will take longer than with a traditional table, but may be just the ticket if your needs are small. On the other end of the spectrum, you may have an in-house UV printer. Some companies now add digital finishing options with their routers, potentially eliminating the need for a separate machine.
CNC routers are a tremendous addition to almost any signshop. They can save time, money and add additional products to the catalog. Just be aware of your need, and make sure you acquire the proper machine for the job.