For tube expanding it is desirable to roll the tube quickly as it prevents work hardening of the tube and less frictional heat is generated. The limiting factors in this balance of speed vs. power are voltage or pneumatic pressure. These either limit the speed or power being produced.
Tube rolling occurs when the tube rotates due to inadequate friction between the tube OD and the hole in the tube sheet. This can cause increased expansion times and decrease the efficiency of the operator. Increasing the friction between the tube and tube sheet and or collar the tube will not rotate within the tube sheet. Increasing the friction can be done using several different methods:
Learn how to quickly change out roll sets to avoid drops in productivity.
Between less tool replacements and faster cycle times, the manufacturer was able to save significant production time by using the 24 Series Expanders.
With Elliott’s 24 Series Expander, this fabricator experienced a significant increase in tool life and ease of use, reducing rework and hassles.
Elliott’s Single Roll Beading Expander saves Keller & Associates on labor costs as compared with the manual method of using an air hammer and beading tool which takes three operations instead of one.
With parallel pin expansion, the rolls are set parallel with the mandrel with zero feed angle. This means that the mandrel will not self-feed as a traditional expander would. Instead, the mandrel is pushed through the expander by force, in most cases hydraulic, allowing the tube to expand.
To ensure high-quality tube expansions, the tube wall must be reduced by a predetermined percentage and be consistent with each expansion. In order to complete the job efficiently, it is important to achieve the maximum expander tool life in order to reduce cost and downtime.
A mechanical tube joint is formed when the outer diameter of the tube is compressed against a fixed container. Rolling to the proper wall reduction will decrease the chances of under rolling and over rolling a tube, creating higher quality mechanical joints.
