Care should be exercised in the placement and expected duration of the welds.
Typical Teflon® or Fluorogold® Slide Bearings, called out as FC-1010-CS (1/8 carbon steel, 3/32 Fluorogold® or Teflon®), are welded in place. Several things to watch for are;
Delaminating
The bond holding the Teflon® to the steel backing plate can break down due to the heat generated by the welding process. If the slide material delaminates it loses its durability and will lead to premature failure. To minimize heat and avoid delamination tack welds should be limited to approximately 1/2” long. To further guard against de-laminating the slide bearing can be fabricated with a 1/4” lip (Fig. 1)
Fig. 1
Shown is the left edge of two slide bearings. Tack welds are limited to 1/2” length to avoid delamination. The bearing on the right has a 1/4" recessed lip for added protection (red arrows). Note, the outer dimensions of both bearings are the same.
Access for Maintenance
Four welds are typically enough to secure the bearing plates. Try to confine them to the outside edges. Fig. 2. This leaves the welds in the most accessible position if the assembly ever requires replacement.
Fig. 2
Four tack welds are positioned
on the outside edges to allow for access if the bearing assembly requires maintenance or replacement.
Additional Welds
If additional welds are required, keep them near the corners on the inside edges. Guard against heat build up by welding on alternating sides. As shown in Fig. 3, the red arrows are welded, then blue arrows and the pattern is continued until complete.
Fig. 3
The additional welds are located near the outside edges. This provides better access for maintenance in the future. The welds are limited in length and applied in an alternating pattern (red arrows, blue arrows) to minimize heat.
Full Perimeter Weld
When a Slide Bearing assembly will face exposure to difficult environmental conditions a full perimeter weld may be specified. This prohibits any moisture or contaminants from collecting under the bearing and causing corrosion. However, it will increase the possibility of delamination. To mitigate that a 1/4” recess lip is essential and a stitch weld pattern should be employed. Stitch Welding is the same pattern as in Fig. 3, but the process is continued until the entire edge is sealed. (See Fig. 4)
Fig. 4
Full Perimeter Weld. To avoid excessive heat and
possible delamination tack welds are applied in an alternating pattern. (shown with the first pass in black, then red, the blue.) This pattern is continued until there is an uninterrupted weld around the perimeter.
There are many additional variables that can affect bearing assembly applications. The Steel Supply Company can assist with technical information and installation procedures.
Rotational / Rubber Bonded Slide Bearings
Fluorogold® / PTFE Alternate Uses
For assistance with your project, please feel free to call or mail.
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