6Phone: 516-328-3970www.technocnc.comTechnical SectionRouter to invest in, there are several important aspects toconsider. The end result of CNC Router design andconstruction should be greater than the sum of its parts.The quality of a CNC Router's components, in addition tothe history and reputation of the company, should beweighed heavily during the buying process.This technical section will cover vital aspects to thebuying process, such as: spindle options, tooling basicsand maintenance, fixturing requirements, CNC accessoriesand software; items which, when looking to purchase aCNC Router, should be considered without exception.However, the first topic to be considered is the router itself.The CNC Router market runs the gamut from hobbyistmachines at $5000, up to huge CNC machining systemsthat cost in excess of $200,000. The idea is to find the CNCRouter with the right price to performance ratio within yourbudget.Size and space requirements should be decided uponbefore other more complex CNC features. Allotted shopspace in relation to a routers work envelope can determinewhether a 14" x 19" tabletop model or a 59" x 120" CNCsystem with a moving gantry are the right machinespecifications to research.After deciding on a machines footprint (e.g., 109" x 149"x 60"), the element that greatly determines the quality,durability and overall performance of a CNC Router isfound in its drive components. Basically, what method isused to move the machines axes. Technos CNC Routersutilize THK rails and ball screw drives, which providesmooth play-free motion, require minimal maintenance,provide excellent accuracy and long life. The placement ofthe ball screw is in the center of the axis of travel, whicheliminates the possibility of racking (i.e., when the systemtwists due to misalignment). This also ensures that theTechno machine does not need to be realigned ever,causing no wear on the drive or carriage system. Eliminatingthe downtime spent repairing damage from racking, resultsin increased productivity and profits.Some CNC Routers use other drive systems, such asthe rack-and-pinion gear drive. The racks are typicallyinstalled on the outside of the machine, thus exposed to theelements. As the machine cuts, debris collects on the rack.These foreign materials get ground into the racks andgears, causing more friction in the drive system which, inturn, causes wear and makes the machine less accurateand unstable.In a rack-and-pinion system, there are typically two drivemotors required to run the one axis (one on the right sideand one on the left side of the machine). The two motorsmust stay completely in sync with one another. When thesemotors get out of sync, racking occurs. Racking deformsthe gears within the system, wearing down the components,and the unit itself can be jolted out of square.The choice between what drive motors to use firstcomes down to either servo or stepper motors. Servos aretypically the more expensive motor, but certain Micro-Stepper motor options bring parity to the purchase price.The big difference between the two motors is in how theyrun. Steppers, as the name implies, have a set number ofsteps per revolution. Movement is measured assuming thateach commanded step has been completed. Most steppersare run in what is called an open-loop configuration. Thismeans that the location of an axis is not verified on anongoing basis. The motor is commanded to move a certaindistance and it is assumed the move is successful withoutverification. This can cause problems when excessivevibration or resonance from the motor/machine constructioncan cause the stepper motor to lose steps or even stall.CNC Router Components