Yardley self-tapping inserts are ideally suited for high volume assembly operations because of their easy, quick installation. Inserting a self-tapping insert is as simple as driving a self-tapping screw or tapping a thread. A drilled hole of correct size must be provided, driver tool is applied to insert, driver and insert are positioned over the hole, insert is driven (turned) home and the driver is backed off, leaving the insert installed. The insert cuts its own threads as it is driven into the base material. The methods listed below can be used to install Yardley TRI-SERT and FIBERSERT inserts.
Because it is driven by its internal threads, a different driver is required for each insert size. Thread cutting can be accomplished on either end because there is a lead in both ends of the insert. Alignment is important and the insert should be used with a hand tapper or a tapping head attachment on a drill press without a lead screw. For applications in recessed areas or close to walls or ribs, a Yardley Extension Driver may be used to facilitate installation. Inserts should be installed flush or below material surface. Thus, when one assembles a bracket and screw to the insert, the load is not transmitted directly through the insert but to the surface of the boss or the material in which the insert is installed. This is especially important where vibration is encountered.
The ultrasonic process converts electronic energy into high frequency mechanical vibration. The ultrasonic equipment operates from a normal 60-cycle line current and converts this to an output of 20,000 cycles per second. The output of the power supply received by the ultrasonic press that is similar to an arbor press in that there is a longitudinally moving arbor or tool. In this moving arbor, the oscillating electrical input of 20,000 cycles per second is converted to a mechanical vibration of 20,000 cps.
In the production operation, an insert is placed on the pre-drilled or pre-molded hole and the horn of the ultrasonic tool is pressed down on the insert. The horn transmits ultrasonic vibration to the metal insert and the friction from the vibration of the insert melts a thin film of resin at the metal-plastic interface. Pressure from the ultrasonic tool forces the metal insert into the hole until it is completely inserted. When the ultrasonic tool is removed, the melted plastic next to the insert solidifies and the insert is locked into place.
Since only a thin film of the resin is melted, residual stresses in a boss are minimized. Insertion time is relatively fast and the ultrasonic method is ideal for automatic, high production operations.
Cored or machined holes should be the correct size for the insert used. Excess melt squeezes out if the hole is too small. If the hole there is a reduction in stripping torque and pull-out force. Generally, the boss diameter should be twice that of the insert diameter. A larger boss diameter increases the stripping torque. Please consult our engineering department on your applications.
The epoxied-in process consists of drilling a hole or having a hole that is slightly larger or a lot larger than the overall diameter of the inserts. The hole is then filled with epoxy, and the insert is installed into the epoxied hole. The epoxy will take up any extra space inside the hole, adhering the insert inside the plastic, wood, ceramic or other base material.
This is the easiest installation method. Place the Insert pilot into the hole and use a hammer or arbor press to seat it. A piloted, extended punch can be used for recessed locations. In high volume applications, an automatic insert driver can be used.
During the molded-in process, inserts are placed on pins inside a mold housing. The base material is then injected into the housing, surrounding the inserts After the mold has cooled and set, the inserts effectively remain where they were placed on the pin locators inside the mold.