Clamping jig for computer numerical control (CNC) machining

The invention discloses a clamping jig for computer numerical control (CNC) machining. The clamping jig for CNC machining comprises a rack, a placement table, an adjustment groove, gear teeth, a powerbox, a transmission shaft, a transmission gear, a roller, pressing plates, an installation groove and a first drive screw rod. The placement table is arranged on the top part of the rack; a holding groove is formed in the placement table; the adjustment groove is formed in the placement table; the gear teeth are arranged on the bottom of the adjustment groove; the power box is slidably connectedto the outer side wall of the placement table; the transmission shaft is connected to the drive end of the power box and is arranged in the adjustment groove; the transmission gear sleeves the outer side wall of the transmission shaft and meshes with the gear teeth; the roller sleeves the outer side wall, held in the holding groove, of the transmission shaft; the pressing plates are uniformly distributed on the outer side