a fiber placement machine has a head for controlling fiber tows running from an upstream supply creel to a downstream work laydown zone , and the head includes a bracket supporting a presser member which impresses and compacts the fiber against a workpiece . the head includes a relatively rigid fiber guide assembly and a drive for moving the fiber guide to an advanced position near the presser member and a retracted position away from the presser member . in the advanced position , fiber tows run uninhibited through channels in the fiber guide . however , when it is desired to cut the fibers , the fiber guide is run to the retracted position , at which point the guide is clamped to the incoming fiber tows . after the exiting cut fiber has been laid down on the workpiece by the presser member , the incoming fibers may be restarted by driving the fiber guide and its clamped fiber tow to an advanced position where the fiber tow end may be grabbed in the nip formed between the presser member and the workpiece . at such moment , the fiber guide clamp is released to again permit free running of the tows through the fiber guide .