Re: New Build Consideration - Direct Drive or Pulley
You may actually have the space for direct connection, depending on your design. You usually need to space the linear bearings of an axis somewhat apart for rigidity to prevent torque loads on the bearings (typically 6"-12"). That means the actual stroke is that much shorter than the length of the linear rail. It also means the screw can be shorter than the rail and if designed properly the combined length of the screw and motor with coupling may fit "into" the machine instead of the motor hanging out. Example: I have 48" rails for x-axis and have the linear bearings spaced 12" apart, leaving 36" theoretical max. stroke (practical somewhat less). This 12" reserve is sufficient for the end bearings, the coupler and 4" long dual shaft NEMA34 motor with 20mm synchronizing belt to the other side screw. It all fits under the rail.
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