Sawmill - Design Rationale

Things the sawmill must be able to do. See Sawmill Analysis for calculations based on these requirements.

• Must adhere to OSE Specifications. (Open documentation. Low cost and easy to manufacture/replicate. Design for life, disassembly, repair. Robust, multipurpose.)

• Must be able to cut about 2400-3000 linear feet of dimensional lumber per day.

• Must handle up to 3000 lb logs.

• Must cut 4x4s and flat 2x of large width.

• saw wobble specification 1/16"

Motor Rationale

• Must use hydraulic power from LifeTrac.

• Power is about 40 hp - available from 55 hp Deutz, at .72 system efficiency.

• Hydraulic motors utilize 24 gpm at up to 3600 PSI. Each motor is 40 hp, around 700 RPM.

• 2 Cushion valves are used for stopping in bidirectional configuration.

• 2 spool control valve needs to handle the full fluid flow (24 gpm) to each motor.

• To use power effectively, one should be able to control the amount of flow to each of the two

motors, from full power in one to full power in the other.

• Main blade RPM - 1500 RPM.
• Edger blades - 3500 RPM.
• Simple pulley system, with single pulley of 3x for main blade.
• Double pulley for edger blades, about 2.5 ratio for each.

Platform Function Rationale

• Needs a platform that will be able to hold the weight of the motors, pulley system, blades, and frame.
• The weight of the platform will be about 25 lb. per motor, etc for a total of about 200 lbs.
• The platform must be stable enough to make straight cuts.
• The platform should be able to roll in the x axis.
• The platform must move precisely and hold securely in the y and z axes.
• The y and z axis movements must be about 3-4 feet for large logs.

Function List

• blades with insert teeth would be best to use, but maybe expensive
• 2 edger blades on same axle
• 2 edger blades are adjustable
• Move onto hydraulic log handling later
• Move on to automatic sawmill operation with remote control, for ease of cutting.
• Allow for log turning in addition to taking slices out of the wood
• Safety cage around blades
• Blade cooling soapy water?
• Logs loaded with tractor loader
• Mechanism to secure log to track
• use bearings to ride on a flat track?

Log Holding and Blade Direction

• The blade must spin into the product and into the table or stops or whatever is holding the substrate being worked. Otherwise we make missiles.