What are your specs?

1. what % of each
2. what are their relative densities?
3. how intimately do they have to be mixed
4. what batch size do you want
5. what space & time constraints do you have for installing the machine & completing a batch, or is this a one-off?
6. what are the particle sizes- are there possibly issues with carryover into ventilation/dust collection that would dictate a certain type.
7. is the mixing completely dry or are there liquids involved?
8. do you already have a specific type of mixer in mind?
9. if you do & want to establish speed requirements from this, please list the details of the machine as well.

This can be done in anything from a kitchen blender to an industrial ribbon blender that can do a truckload at a time. I would suggest you start by searching Dry Blenders on Globalspec if you haven't already done so, and reference what the manufacturers spec for their machines.

Direct your questions to:

Powder Mixers - Powder Mixers Manufacturers,Powder Mixers ...

Blending Equipment - Blending Equipment Manufacturers,Blending

" What will be the rpm of blade suitable for homogeneous mixing."

You can experiment/research, by running your mixer/blender at various speed. Armed with the resultant data, you can arrive at the best solution to your dilemma.

You will get no where if you concentrate only on RPM,especially with materials being mixed have radically different characteristics. Apart from RPM the the design of the mixing blade will make huge difference. There is no way but to go through proof of concept prototype and freeze the parameters.

Very well said. I too have been involved in a similar mixing technology. It can be unbelievably complex. Definitely not as simple as varying RPM will produce homogeneous mixture output.

Eureka! You have found the source to your solution. Now you can acquire the user right from poster at #6.

Consider a vibration type mixer. Additional media can be added such as smooth stones or ball bearings or any other stuff, as long as it won't compromise your final product, to make the mix more active. These can be easily screened out at the end of the mixing cycle. Vibratory devices like the ones we used to use for deburring small parts can be used for all kinds of things, including mixing. FMC sells a lot of different vibrators that can be attached to all kinds of containers. I found the big man made stone "bowls" to be the best. Their rigidity and weight seem to help the process and they are much quieter in operation than large metal tubs. I know this is probably an unusual way to go, but it could prove quite controllable and efficient unless you are talking huge quantities. I have not been invloved in anything larger than 150 gallon.

OP has not said of the degree of homogenization of PTFE and Bronze.

I make sense to me that the mixture need to be near perfect homogeneity. Downward percolation, upward percolation, diffusion, load and diameter of bronze and PTFE, fine control of frequency of amplitude of vibration etc. need to assessed in a laboratory before knowing whether at all the vibratory mixer is suitable.

Hard highly technical efforts are needed.

Technical forums like this can give no more than a general idea.

I defer to your expertise. But I will say that when mixing "fine" (a vague and inadequate term) "materials" (another gross generality) then "vibration"(a term encompassing a wide range of physical motions and frequency) can yield superior homogeniety(I didn't know that was a word but I like it). A small scale vibratory tumbler, with both adjustable stroke and frequency, and additional mixing media of various types, can provide enough testing data to assess suitability. As you say however, advanced laboratory testing will always lead to the best results. But that is not always a viable option nor economically appropriate. And may I add that sometimes a simple rotational horizontal tumbler can do the job, since it overcomes density issues better than paddle type verticle mixers. And thank you for your comments and clarification.

I appreciate your point of view.

Normally Bronze + PTFE composite is useful in applications which undergo high mechanical loads or high-speed rubbing contacts where the bronze filler supplies the strength and conductivity to carry away excess, unwanted heat. Naturally it is vital to have maximum uniformity of particle distribution for good thermal conductivity as well as uniform mechanical strength. No wonder Mierneal above "took us eight years of expensive and frustrating R&D to develop the techniques required for consistent results blending PTFE with bronze as well as a range of other metals and additives." I can appreciate the frustration of uniform mixing given the widely varying Bronze bulk density of 7400-8900kg/ m3 and PTFE Bulk density 2200kg/m3. It is a very challenging issue.

In reference to the "Vibration-type Mixers", and dependant on how much/how often and what quality of mixture you're looking for I'd say check out my company's website at: http://www.resodynmixers.com/ .

I'll be done this Friday, but they'll still be around selling RAM Mixers to those who require them. Perhaps one of the company's from the previous lists are Resellers, but this is the real deal.

Take care now, Gary Vink