UBUCIKO
UBUHLE NEMPILO
UBUCIKO BEZANDLA
AMASIKO NOMLANDO
EZOKUZIJABULISA
IMVELO
UKUDLA NEZIPHUZO
REVERSE ENGINEERING
IZAYENSI
EZEMIDLALO
UBUCHWEPHESHE
IZINTO EZIGQOKWAYO
PTFE (Polytetrafluoroethylene)
On 6. April 1938 Roy Plunkett at DuPont opened the valve on a cylinder of tetrafluoroethylene gas, a candidate refrigerant, and nothing came out - though the cylinder still weighed full. Sawn open, it held a white waxy powder: the gas had polymerised by itself. The powder resisted every solvent and acid tried on it, did not melt like other plastics, and almost nothing would stick to it.
**US 2,230,654**, "Tetrafluoroethylene polymers", Plunkett, assigned to Kinetic Chemicals, granted 4. February 1941. Its first claim is two words: "Polymerized tetrafluoroethylene."
**Tetrafluoroethylene is explosive and is never handled outside a plant.** You build what the material is for: a hinged tilting ramp that measures the coefficient of friction of PTFE against steel, beside nylon, acrylic and steel itself.
Oqalayo
3 hours
Imiyalelo
1
1
The rig
The rig
The whole rig: a 400 mm base, a hinged ramp with a steel strip on top, a prop under the raised end, and a faced sled.
2
2
Cut base and ramp
Cut base and ramp
From 18 mm plywood saw two boards 400 x 120 mm. Sand the edges.
Izinto zokwakha zalesi sinyathelo:
Ishidi le-plywood1 ucezuAmathuluzi adingekayo:
Isaha Sesandla
Irula Lensimbi
Isibambo esiyi-C3
3
Hinge them
Hinge them
Lay the boards end to end and fit the butt hinge across one short joint with 4 wood screws, pilot-drilled 2 mm. The ramp must lift from flat to 45° without rocking.
Izinto zokwakha zalesi sinyathelo:
Ihinji lomnyango1 ucezu
Izikulufu zokhuni4 izicucuAmathuluzi adingekayo:
Ibhola Elingenantambo
Isethi yamabhola okubhoboza ebhokisini
Isethi yezikulufudrayiva4
4
Fit the steel counterface
Fit the steel counterface
Stick a 360 x 100 mm strip of mild steel sheet to the ramp's top face with double-sided tape. Wipe it with isopropyl alcohol - grease halves any reading.
Izinto zokwakha zalesi sinyathelo:
Ishidi Lensimbi Ethambile1 ucezu
Itheyiphu enamathela nhlangothi zombili1 umqulu
Utshwala Be-isopropyl 99 %10 mlAmathuluzi adingekayo:
Izibuko Zokuphepha Ezicwathile5
5
Make four sleds
Make four sleds
Saw four 60 x 60 mm plywood blocks. Face one each with PTFE, nylon, acrylic and steel cut to 60 x 60 mm, fixed with double-sided tape. Clean every face with alcohol.
Izinto zokwakha zalesi sinyathelo:
Ishidi le-PTFE1 ucezu
Ishidi le-nylon (6/6)1 ucezu
Ipuleti Le-akhriliki1 ucezuIshidi Lensimbi Ethambile1 ucezuItheyiphu enamathela nhlangothi zombili1 umquluAmathuluzi adingekayo:
Isaha Sesandla
Ummese wemisebenzi6
6
Tilt until it goes
Tilt until it goes
Set a sled 100 mm from the top. Raise the ramp slowly, about 1° per second. Stop the instant it slides and read the angle finder on the ramp. Five tries per sled.
Amathuluzi adingekayo:
Isilinganiso Se-engeliIrula Lensimbi7
7
Load it
Load it
Repeat the PTFE sled with a weight taped on top. The angle should not change.
Amathuluzi adingekayo:
IsisindoIsilinganiso Se-engeli8
8
Angles into friction
Angles into friction
Ilayisha incwadi ye-Jupyter…
9
9
History & Context
History & Context
**What the patent specifies:** the polymer of tetrafluoroethylene itself, a solid insoluble in ordinary solvents. **Modern build (derived):** machined PTFE sheet against clean mild steel on a tilting plane.
Its first large use was seals and gaskets for the Manhattan Project's uranium hexafluoride plant, a gas that attacked everything else. DuPont registered Teflon in 1945; non-stick pans followed in the 1950s, and stretched PTFE became Gore-Tex. Its limits: it creeps under steady load, wears quickly without fillers, cannot be glued without etching, and above about 260 °C in use it begins to give off harmful fumes.
Izinto
9- 1 ucezuIsibambeli
- Ihinji lomnyangoikhomishini engu-10%1 ucezuIsibambeli
- 4 izicucuIsibambeli
- 1 ucezuIsibambeli
- Isibambeli
- Isibambeli
- 1 ucezuIsibambeli
- 1 ucezuIsibambeli
- 1 ucezuIsibambeli
Amathuluzi Adingekayo
10- Isibambeli
- Isibambeli
- Isibambeli
- 1 vendor sell this, none ship to you yetIsibambeli
- Isibambeli
- Isibambeli
- Isibambeli
- Isibambeli
- Isibambeli
- Isibambeli
Amafayela omklamo
1Ama-blueprint ahlobene
Lama-blueprint abelana ngolwazi — amasu, izinto noma izimiso
CC0 Isizinda Somphakathi
Le blueprint ikhishwe ngaphansi kwe-CC0. Ukhululekile ukukopisha, ukuguqula, ukusabalalisa, nokusebenzisa ngaphandle kwemvume.
Sekela uMenzi ngokuthenga imikhiqizo nge-Blueprint yabo IKhomishane Yomenzi kumiswe ngabathengisi, noma dala inguqulo entsha yale Blueprint bese uyifaka njengoxhumaniso ku-Blueprint yakho ukuze wabelane ngemali engenayo.