However, the production of these bushings is quite expensive, especially for larger quantities, as the lubrication grooves have to be made individually on appropriate milling machines or lathes. The possible combinations of the different metals are manifold, which is not only due to the basic metals available for selection and their combinations, but also because these metals can in turn be used in different proportions.
In view of this diversity and without metallurgical details, a detailed comparison is beyond the scope of this blog. However, here is a rough overview of some common alloys and their specifications:. There are many other variants that are suitable for a wide range of applications depending on their specifications.
Broken down purely to the individual technical values, the two material groups are difficult to compare meaningfully. Like most metallic bushings, bushings made of bronze or similar alloys offer higher mechanical strength values and — at least when lubricated — better pv values. The consideration should therefore take place above all with regard to the framework conditions.
Polymer bushings, for example, often offer cost savings due to the possible elimination of lubrication and more cost-effective production. In addition, depending on the polymer compound, the pure material costs can also be significantly more cost-effective.
The elimination of the need for externally supplied lubrication also results in further advantages in terms of dependability and maintenance of the bushings. Furthermore, weight savings due to the lighter material are also not insignificant, depending on the application. In every plain bearing application, these advantages and disadvantages have to be weighed up against each other.
However, not all of these aspects play a role in every application. In a fluid dynamic or hydrostatic bearing, the bearing surfaces should never actually touch as they are held apart by pressurised lubricant.
The specific materials matter as well for example aluminium-on-aluminium sliding would be much less desirable than cast iron on cast iron. I can think of one main reason why you might want to make them out of different materials: Differing hardness. What this means is that only one of the materials should 'wear' and then you could design it so that this part could be changed out easily. For example: if you had something following a guide, you wouldn't want to have to replace the whole guide when it started to wear, so if you make the thing that follows the guide softer then it will wear and you can just replace that.
But yes. Without more information I can't really give any more advice. That statement is not universally true though. For a sleeve bushing, you want a soft slippery material with sufficient yield strength to withstand any deformation of the hole surface during operation. You want as close a possible fit as you can get, you want it to feel slightly snug with a small amount of friction.
Spin the parts while not under any load and the rotating surface of the shaft will lap the bushing until there is zero friction and it helps to move the parts in and out along the axis slightly to eliminate as much material as you can from the bushing surface until it rotates freely. If you do all these steps and tolerance your parts correctly and use the right materials, you will have a perfect rotating bushing joint.
Make sure to factor in the loads it will be operating under, and make sure to follow the guidelines above, and these kinds of joints can withstand a few hundreds of pounds with very low friction comparable to a ball bearing and gets smoother and looser as time goes on and the bushing continues to wear.
You just want to prevent deformation and reduce friction. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why use bushings of different material than what they contact? Ask Question. Asked 5 years, 9 months ago. Active 3 years ago. Bronze Bushings With all the benefits of plastic, where does that leave metal? SAE is also used for applications requiring food-grade quality.
Cast Bronze: The extra corrosion resistance with these alloys typically bronze with tin, aluminum, or silicon makes it especially useful in wet environments. Bunting Bushing Solutions Whether you need bronze or plastic bushings, Bunting Bearings can fill your needs.
Nylatron : Cost-effective and self-lubricating, this is a nylon modified with molybdenum disulfide lubricant powder. B U : This unique composite features a steel backing and a bronze layer impregnated with PTFE for a strong mechanical bond. Cast Bronze : A full range of leaded tin bronze bearings are in stock plus a full range of sleeve and flanged bushing made from ECO BRONZE which in independent tests proved to be superior to other cast lead-free materials.
Oil-Impregnated Bronze Bushings. Leave a Reply Cancel reply You must be logged in to post a comment. Providing Quality Engineered Solutions Since
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