Rubber Bellows are used as a cover or expansion joint to protect device or machines, which are made by rubber compression molding, rubber injection mold or extrusion tool.
Rubber Bellows are designed as a cover mainly protect against dust, water, oil, grease, acids, bleaches, spatter or other environment elements.
Rubber Bellows Main Structions and Shapes
Straight Convolution Rubber Bellows Spiral Convolution Rubber Bellows
Concentric Rubber Bellows Tapered Rubber Bellows
Reasons of Rubber Bellows' major defects:
1. Flashing is too big: to solve this problem, we need to pay attention to 3 points when production; the first one is mold-design, second one is workers' skill about removing flash, and the production technology is also very important, if molding pressure is not enough, will also make the flash hard to be removed.
2. Mold misalignment & uneven wall: this problem mainly caused by mold tool, like mold-making precision, misalignment of upper mold and down mold, datum angle & the 4 located pins are not accurate enough.
3. Lip cracking: the situation is relative to raw materials hardness & durometer, products' structure, and die-cutting tool.
Rubber Bellows Materials adoption
|RUBBER COUMPOUNDS TYPES AND REFERENCES|
|Aging Weathering |
|Oil& Grease |
|Water Swell Resistance||Flex-Fatigue||Economy of|
|CR||-40F to 250F||Good||Good||Average||Very ood||Good||exposure to refrigerants,|
can be compounded for FDA applications
|Nitrile||NBR||-22F to 212F||Poor||Very Good||Good||Good||Very Good||Automotive Applications,|
Good Oil Proof
|Ethylence-Propylene||EPDM,EPM||-60F to 300F||Very Good||Poor||Very Good||Good||Very Good||Outside Applications,|
Good Weather Proof
|Silicone||VMQ||-75F to 450F||Very Good||Average||Very Good||Very Good||Average||Medical Applications|
|Fluorocarbon||FKM||5F to 390F||Very Good||Very Good||Good||Average||Poor||Rubber King,|
Rubber Bellows Design Guide
Rubber Bellows Some Typical Applications
Rod & Ball screw covers
Piping penetration seals
Fan duct connections
Compressor and engine intake and exhaust manifold connections
Different Silicone Rubber Bellows durometer demands, surface demands, parting lines demands or rubber flashing demands have different production difficulty and production cost. Epecially for mold-making technology demands, compression mold steel choice, mold maintain when mass production etc.
Custom Rubber Expansion Bellows Requirements:
1. Offer 2D, 3D design drawings or samples, and also tell us your sizes telorance demands.
2. Bellows Materials Demands: Rubber, Silicone, EPDM, Nitrile, etc, or tell us operating environments, functions etc.
3. Durometer Demands (Hardness Shore A):
4.. Silicone Bellows Surface Demand
5. Working Environmment Demands
6.Silicon Bellows Flashing Demands etc.