Tray with flat bottom reference surface

Abstract

A molded component tray includes a component housing portion having a plurality of component pockets. The tray has a flange around the component housing portion defining a perimeter of the tray. A flange top surface in one embodiment is below the component housing top surface. A flange bottom surface includes recessed areas positioned in alignment with mold ejector pins which may contact the flange bottom surface, and alternatively in alignment with mold ejector pin marks on the flange top surface. The depth of the recesses is greater than the height burrs left by the ejector pins, thereby leaving the tray bottom surface free of burrs caused by ejector pins. Alternatively, when one tray is stacked on top of another, the recesses in the bottom of an upper tray can be positioned to allow clearance for ejector pin marks on the top of the flange of a lower tray.

Description

RELATED APPLICATIONS [0001] This application is related to U.S. Application entitled Bare Die Tray With Flat Datum Surface filed on the same date as this application, bearing attorney reference 0678100301344 which is expressly incorporated by reference herein.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to trays for use in carrying components such as semiconductors, and more particularly to a tray having flat datum surfaces and configured to avoid calibration variations due to mold injector pin burrs imposed on the tray during manufacture. [0004] 2. Description of the Related Art [0005] Small components such as semiconductors are often stored or shipped in molded plastic trays similar to tray 10 shown in FIGS. 1A and 1B. In the molding production operation, ejector pins are used to push / eject the tray from the mold casing. Burrs are caused from molten plastic filling the circumferential gap between the ejector pin and the ejector pin hol...

AI Technical Summary

Benefits of technology

[0007] It is an advantage of this invention in that it provides a component tray that has improved reference surfaces.

[0008] It is a further advantage in this invention in that it adds recessed areas for contact with mold ejector pins so as to avoid uncertain contacts due to burrs, and therefore provides a flat datum surface.

[0009] It is a still further advantage of this invention in providing a tray that in use maximizes the accuracy of calibration of automated equipment.

[0010] It is another advantage of this invention in providing a tray that can be stacked accurately.

[0011] It is another advantage of this invention in providing a tray wherein ejector pin blemishes do not affect stacking of trays and calibration.

Problems solved by technology

Part ejection is a forceful process, and the pressure of the pins on the tray leaves burrs / marks / blemishes on the tray surfaces.

These burrs cause variations in the effective tray thickness and as a result trays cannot be stacked with a consistent height or degree of flatness.

The burrs cause errors in calibration of automated tray handling equipment, and equipment for picking and placing components in tray component pockets.

Removal of burrs would involve additional and expensive machining or manual processes, and generally is not practical.

These distorted / inaccurate reference surfaces limit the ability of automatic machines to accurately pick and place components in the tray.

The burrs 12 and 14 also cause an uncertainty in the height and straightness of a stack of trays 10, causing problems with automatic stack handling equipment, as well as problems with shipping containers and clips.

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