Some three or four - maybe more years ago, but this century - there was an article in the RSGB RadCom magazine by a guy who made his own ceramic coil formers. These were fairly big for TX use, but doubtless the principle could be applied to smaller ones.
Bakelite ones were moulded, hopefully without a filler of wood flour, but rather of powdered mica. (Millen's 'Micalex', I believe) Paper ones are just wound: the better resin bonded paper would be filled with resin after vacuum treatment.
I have made my homework:
In this difficult time understanding is the key to the future.
It may trigger an ideas.ferrites,ceramics,metal parts have something in common;
Easy introduction to the technology of powder compacting into product
Solid state sintering is the process of taking metal in the form of a powder and placing it into a mold or die. Once compacted into the mold the material is placed under a high heat for a long period of time. Under heat, bonding takes place between the porous aggregate particles and once cooled the powder has bonded to form a solid piece.
Sintering can be considered to proceed in three stages. During the first, neck growth proceeds rapidly but powder particles remain discrete. During the second, most densification occurs, the structure recrystallizes and particles diffuse into each other. During the third, isolated pores tend to become spheroidal and densification continues at a much lower rate. The words Solid State in Solid State Sintering simply refer to the state the material is in when it bonds, solid meaning the material was not turned molten to bond together as alloys are formed.
One recently developed technique for high-speed sintering involves passing high electrical current through a powder to preferentially heat the asperities. Most of the energy serves to melt that portion of the compact where migration is desirable for densification; comparatively little energy is absorbed by the bulk materials and forming machinery. Naturally, this technique is not applicable to electrically insulating powders.
To allow efficient stacking of product in the furnace during sintering and prevent parts sticking together, many manufacturers separate ware using Ceramic Powder Separator Sheets. These sheets are available in various materials such as alumina, zirconia and magnesia. They are also available in fine medium and coarse particle sizes. By matching the material and particle size to the ware being sintered, surface damage and contamination can be reduced while maximizing furnace loading.
1. YouTube videos
Gasbarre 30 Ton CNC Hydraulic powder compaction press
this one is for me manual processing.
Metal powder injection molding
Powder Metallurgy Touches Your Life, Part 1
2010 MPIF PM Design Excellence Awards: Grand Prizes !!!!!
Baldwin Defiance 75A Compacting Press from Detroit Process Machinery
Y30E Rotary Powder Compaction Press
Dorst TPA-45 Powder Compacting Press "For Sale" at Detroit P
2. More complex science and lectures:
Mod-1 Lec-1 Powder Metallurgy - 1
this is lecture of what it is with heavy accent.
Celadon Ceramics Making.avi - YouTube
this link is to skip the only important here is that ceramic is needed of 800 Celsius for 4 hours
Cold Isostatic Pressing.mpg - YouTube
that one is not for home small production but is good for all of powder based products.
melting temperature table for various materials.
Note that for sintering there is no need for such high temperatures
4.Powder metallurgy - Wikipedia, the free encyclopedia
Powder production techniques
5.Loomis - Inside Page
LOOMIS PRODUCTS piston extrusion presses are used to process powdered ceramics, metals, and plastics into a wide variety of profiles ranging from simple cylinders and tubes, to complex honeycomb shapes. With capacities exceeding 800 tons, our piston extrusion presses are available in 9 standard configurations, and are capable of producing parts per customers specifications.
Cold compaction is a process in which powder is compressed at a temperature where deformation mechanics like dislocation or diffusional creep can be neglected
6. Ceramic Materials Mechanical and Electrical Properties - Du-Co Ceramics Company
Mechanical and Electrical Properties of Ceramic Materials
7.Extrusion Press Ceramic,Buy Quality Extrusion Press Ceramic from Manufacturers and Suppliers on Alibaba.com
high alumina ceramic
Min. Order: 100 Pieces
FOB Price: US $0.05-1.00 / Piece
Best quality ceramics for oil
FOB Price: US $ 399 - 436 / Ton
8.Used- Stokes Single Motion, Single Punch Compacting Press, Model 511.6. Maximum
Ham radio forums coil formers
11.Detroit Process Machinery - Inventory of Kilns, Furnaces, Ovens - Buy and Sell Detroit Process Machinery Ceramic Kiln, High Temperature Furnace, Elevator Kiln, Vacuum Sintering Furnace, Sinter Hip
powder industry used machinery.
At the end someone who has good lab and small mechanical lab can move to area of use of both.
so for ebay and military auction hunters it takes less than some of you spend for restaurant and entertainment
including cigarettes withing 2 years to get to all this guy was able to get.
kind of impressive.http://www.youtube.com/watch?v=QHBEHOOsxT4look at minute:
2:33 to 5:22
35:34 to 37:51