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The major frame components of your machine set the stage for it's performance. Long term, any machine tool can only be as accurate and dependable as its original mechanical parts. At Freedom Machine Tool we can optimize tolerances with laser calibration and backlash compensation options, but only after we build and apply the best quality parts we can afford. This is a value-priced machine, but look closely at the pictures; you'll be surprised by the attention to detail.
Our Process
The base is a one piece steel tube, angle and plate weldment. It is stress relieved prior to machining. The bridge is a reinforced steel tube with plate weldments for the rail mounting surfaces. Two steel tube weldments form the column uprights for the bridge. A tubular steel cross member connects the two bridge columns uprights and provides the ball-screw connection point underneath the table. There are 4 bolt points in the two primary frame structures. All component connection and mounting surfaces, drill holes and tapping, and critical part creation are performed on CNC machining centers. Only very minor assembly tasks, such as mounting the air/oil regulator are relegated to hand operations.
Things to Consider
Machines in this price segment vary in frame designs. Some are as simple as 80/20 style, bolt together aluminum extrusion. There are builders that combine steel base frames with aluminum bridge structures in a variety of bolt together and welded arrangements. Other's use all aluminum.
Pound for pound, steel is stronger, has a smaller coefficient of expansion and contraction, and is better at dampening vibration and harmonics that effect cut quality. The less bolt together, the better the dampening qualities, and overall integrity.
Precision machine tool cutting, drilling and tapping adds to the overall fit and quality of the machine. We have seen import frame structures where 1” wide aluminum strips were attached to the steel frame and machined with the router for leveling and mounting the vacuum table. This caused the router table to cup. Why not just weld a more accurate base frame? The grade of steel used in the import machines we have seen is soft and of sub-par quality. The number of poorly hand drilled and tapped holes, and stripped screws were unacceptable. Again, let me stress, not all import products are sub-par, but be sure you look closely so you know what you are buying. These machines are cheap for a reason. They use lots of cheap labor instead of precision machinery, and they use cheap materials and components.
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