Feed Tables & Bridges
Miller Manufacturing, Inc. has designed this infeed system specifically for efficient operation. Our pineapples and powered holddowns provide additional traction over and above the typical infeed system for maximum acceleration to the planer. Our live shear significantly reduces the initial gap that must be closed before the board enters the planer.
Roll positioning changes can be made without stopping production. We provide this labor and time saving feature on our pineapples, powered holddowns, idler holddowns, anti-double up bar and live shears. The holdover on the bridge requires no upstream adjustment as it follows the live shear position.
Feed Table Information
At 1500 FPM infeed speed, a 1/2 second hesitation at the shear area will cause a 12 1/2 foot gap between boards. Reduction in this delay allows the infeed to run at a slower more efficient speed and still provide ribbon feed to the planer. Typically, operators try to compensate for large gaps by increasing the infeed speed, and the higher impact at gap closure causes laps, breaks and snipe. The standard shear promotes corner damage on the boards, pinching against the guide, and friction working against the initial movement to the guide.
Our live shear will reduce the initial gap, reduce board damage and create less board to board friction, allowing better acceleration to the planer. It is set in with the powered face parallel to the lumber line for full end contact with the boards, reducing contact stress and providing a constant driving force toward the guide without pinching. Powered shear users experience reduced board gap and more consistent feeding. The powered face is driven by an adjustable speed gearmotor and VFD with braking resistor. The shear position is remotely adjustable by a switch in the feederman’s console.
Our live shear has given many customers approximately 2000 board feet per hour increased production. It also has allowed customers to reduce their infeed speed by over 200 feet per minute on average.
Our aggressive pineapples are precision milled with a spiral angle that matches the aggressive roll. This gives a coordinated pull on the board to the guide. They are double thick RW90 chrome plated which has proven to give superior longevity to traditional chrome.
Pineapple Roll Tensioning System
Proper position and tension is essential for optimum performance and efficiency of an infeed system. Too much tension causes the boards to be delayed while they overcome the excess pinching action of the roll, while too little will not give optimum traction. Position too high or too low has a similar result. We use electric linear actuators in place of traditional hydraulic cylinders. Each actuator has an air cylinder to counterbalance the weight of the roll. This will allow the pineapple roll to be precisely controlled to maintain consistent tension when boards are present.
We use aggressive spiral rolls under the pineapples. They are double thick RW90 chrome plated for maximum life. The aggressive spirals are milled into the face of the rolls to give additional traction toward the guide and then toward the planer. The remainder of our feed table rolls are spiral cut and also RW90 chrome plated.
The powered holddown is placed immediately after the shear. This will give better acceleration of the boards to the planer, reducing the initial gap and the excess speed required to close it. The powered holddown will also provide you with excellent board containment, reducing the opportunity for boards to double up.
Filler plates are installed between the rolls on the bridge. These plates are one of the four containment means for the boards, allowing the board ends to deviate no more than 3/16 inch from top of the bed roll. With this limitation, boards with bowed ends that would otherwise drop down between rolls are now contained. Combined with top control, double ups are significantly reduced.
The holdover is full length of the bridge with an adjustable air cushioned downstream end to yield when crooked boards pass. The upstream end is pivot mounted to the shear, eliminating the need for adjustment.