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That page consists discussions related to metallurgy and 3D printing on the lunar surface
(and at Adobri Lab).
ON FEBRUARY 03, 2014 12:39 AM Results on one metallurgy experiment (negative). Cubesat flat antenna design.
Thermal stabilized for vacuum oven did not work well. And all PCB for antenna has to be recalculated (no micro-strips on small square area).
SNAFU as usual.
ON JANUARY 27, 2014 10:40 PM Software, metallurgy, Antenna 2.4Ghz
Last week business. Redesigned antenna. Trajectory calculation capable to do distributed calculations. And re-fined vacuum chamber/ oven showed better performance.
Сводка за прошлую неделю ;-)
Теперь антенна будет плоская - несказанно рад - можно запихнуть в одну PCB, в то время как раньше она занимала минимум 8 х 8 х 96 мм. ПСБ упаковываются с двумя другими (отражателями будут) очень компактно. Развертка всей конструкции две пружины. Вся электроника должна уместиться на двух 3.5 х 2.5 дюйма - это значит при 20 часовой в неделе - 6 недель - 10 часов на прототип - 2 днф изготовление - 2 дня почта - 10 часов на проверку и пайку - и цикл повторяется - итого на третьем цикле - рабочая элктроника. Останется только промазать полиуриетаном (специальный и жутко дорогой). (Но софтвер еще не готов).
В выпечеке благодаря Виктору и Боре начали получаться постоянные результаты. Первое - печку надо чистить (нужен древестный уголь - только в русских магазинах можно купить - дуристика - в аптеках города нет - используют только в госпиталях - чтобы лечить наркоманов). Вторая причина - нужен температурный стабилизатор - что-то большое и железное, чтобы убрать гардиент температуры.
Перерисовал пакет с двумя двигателями - поместил на G+.
Переписал план полета.
И нужно закончить эту дурацкую веб-сайту - влез незнаю зачем - все повыпендиваться хотел - чтобы красиво было - нахрень красоту спасающую не знаю кого - но уже доделал - вэб-сайта готова к распределеенным вычислениям.
Sorry - no time for translation - if some body read this - use Google translate to English, pls.
ON JANUARY 20, 2014 05:52 PM Extruder, material for 3D printing, Gear for Ground station, etc.
Paste extruder finally showed up, material for 3D printing - copper-tin, copper-zinc, titanium-copper. gear for ground station and rover, vibration testing table.
ON JANUARY 15, 2014 04:21 PM Metallurgy. No titanium-aluminium alloys yet.
Not much results for 3D printing. 3 type of alloys so far - the titanium-copper (under layer of a titanium powder - argon is not good for small type owen, and helium conducts heat) - tin-copper , and zinc-copper. Aluminum is not successful at all. Needs to find blocker of O2 and N2 started to be liquid at 500C and boiling point up to 1100C. Window's glass is one possiblity. Tin and zinc - other.
Post office started to deliver delayed by Christmas items from 3D printing factory . Irony - 3D printer waits 3D printed parts to be able to 3D print 3D priter itself - what kind of Christmas's delays will be expect in case of 3D printed internet?
ON DECEMBER 24, 2013 02:35 PM measurements planning for Ti Cu alloy
There are limitations what we can choose as manufacturing facility for rover's parts. Best solution is to make parts in-house, but that require metallurgy and 3D printing at hand. Measuring strength of alloys is one of "must be" part.
ON DECEMBER 11, 2013 02:23 AM Titanium alloys investigation
That (Ti75%Cu25%) is perfect sample - strongest and solid practically without cavities.
That (Ti90%Ag10%) has cavities - mostly because of low silver. Probably with 20-25% it could be solid, more heavy and strong. Longer time in oven (around 820C) can help to reduce patches of not solidified grains.
- That is 2000 years old technology sample (nothing new in this world) - solid, strong, and non expensive (0.5-0.8 cents per cm^3). Probably that can bring bronze age back to houses.
And needs to find the (easy) way to measure all mechanical parameters of alloys.
Existing paste extruders has that limitations:
- Material for printing limited by a syringe size (10-20 -200 cm^3)
- It is hard to make the small diameter extrusion - viscosity is high.
Probably needs to make the screw extruder. Dry powder is delivered by vibration via the plastic tube (thus less inertia parts for positioning mechanism). Once debugged using dry powder, so through the central part (with ball valve) delivers pressurized water with PVA - water. Ratio liquid / powder adjusted by (a) turning speed of the screw, and (b)the water's pressure. Small 100$ desktop compressor with an automatic pressure control will be preferable.
For the beginning the mold 3D printed from the plastic (for extruder) can be made. Then next step will be to 3D print the extruder itself.
Design with two extruders can allow combining two metals with different heat conductivity and strength.
see more on - http://reprap.org/wiki/TitaniumAlloy
ON DECEMBER 08, 2013 11:13 PM New Titanium alloys for 3D printing.
From left to right.
Titanium 90% Silver 10% = density 4.7
Titanium 75% Copper 25% = density 5.1
Copper 75% Tin 25% (bronze) = density 7.8
Looks like now rover can be fully 3D printed from titanium. It will be less than hundreds euro per 1 cubic centimeter of a titanium and printer will be open source Mendel.
Wow! I do not believe myself.
NOVEMBER 21, 2013 04:47 PM Messages to be printed on the lunar surface.
...in December (in two weeks) I’ll start to print the wheel's spokes for the rover. I need the list of all of our classmates. 16 tires/spokes on the wheel. On each tire can be printed one or two names. Total (with two wheels) == 32 messages / names. Two or three spokes/tires are reserved for investors. Offer is non expensive, but they are picky and do not wish to buy messages. After the discount - one dollar for one message per year, at once, for the entire warranty time.
Therefore, on December I need a list == one name for one tire of our 1976 school class. The printing area on the tire is 1cm x 4cm. The warranty time of the message to stay on lunar surface (to take an account the modern state of space exploration) - one million years. One or two tires has to be reserved for our teachers - their investment into us were priceless.
Moonwalker. (Alex Dobrianski)
Response from Donetsk-
List of the names - (Needs to ask Igor which last name he want to place)
1. Анциферов Валерий
2. Белоусов Игорь
3. Бибик Юрий
4. Васильченко Игорь
5. Геженко Инна
6. Гефтер Валерий
7. Добрянский Александр
8. Елифёрова Галина
9. Кириченко Константин
10. Коган Елена
11. Краснопёрова Ольга
12. Кубарева Марина
13. Лившиц Олег
14. Чайковский (Мальч) Игорь
15. Любашевский Геннадий
16. Милославский Михаил
17. Пашутин Александр
18. Писарев Виталий
19. Плахотный Сергей
20. Плетнёва Оксана
21. Пугач Владимир
22. Сальников Николай
23. Серезентинов Геннадий
24. Скирка Ольга
25. Скокова Валентина
26. Степанель Нина
27. Стешенко Сергей
28. Хасин Станислав
29. Чернявская Наталья
30. Чумакова Светлана
31. Шамович Людмила
32. Шпак Александр
33. Ярёмич Алексей
Хурина Мина Львовна
Белоусова Ирина Викторовна
Борц Илья Яковлевич
OCTOBER 27, 2013 08:13 PM Titanium + Ag + graphene
Titanium 70% + Ag 20%+ graphene (low grade - not expensive) 10%+ 820C + vacuum 10mmHg- perfect mixture = left picture powder was pressed under 1424psi, on right two pictures was much less.
It is nice to have old, broken vacuum oven, impossible to fix.
Just fixed broken part, and - amazing results!
OCTOBER 16, 2013 10:36 PM Happy thanksgiving, Canada. Space Shuttle's Paradox.
Engineer who had made a mistake in design of complex systems, with a technical vital parameter twice less than was required, probably will not be an engineer again.
Best engineers, designers, advisers, economists, managers, did the design of Space Shuttle's system with one of vital requirements - to reduce costs. On the first flight it was calculated to be 5000$ per 1kg on the orbit, at time of full fleets readiness - 1000$, and at year 2000 it should be 100$ per 1 kilogram of payload on Low Earth Orbit. Space shuttle retired, and closest business "SpaceX" asked (in 2011) from Team PlanB about 180,000$ per 1 kg on LEO.
Paradox - engineers who reached The Moon got wrong in the vital parameter of the system 1000 times, not just twice.
"where is the difference?".
Question is interesting from a practical point to find the solution- If for this invisible structure, with antimatter inside, will be interest to make any deal, then path to the moon will be opened again.
----------Translation for my friend Шура-------------------------
Парадокс Космического челнока.
Инженеры допустившие ошибку при проектировании технического параметра системы более чем в два раза (мост построенный до середины реки, например) обычно должны сменить род своей работы.
Лучшие инженеры и экономисты разработавшие систему Шаттл ошиблись в 1000 раз, а не вдвое (на первых полетах стоимость 1 кг доставки на орбиту должна была быть 5000$, после создания флота 1000$ и в 2000 году цена должна была упасть до 100 долларов). Парадокс.
Вопрос - "куда деваются деньги?" - практичен - если эта дырка согласится на какое либо соглашение, то будет реальный шанс долететь до луны.
OCTOBER 11, 2013 07:39 PM Whiskers.
It is not what makes cats attractive in a spring time. That small forest is from tin, crystals grown in vacuum - "tin whiskers". Nothing attractive, if to keep in mind that 1mm whisker (grown in 1 hour) can short-circuit two electronic conductors on PCB.
To properly deal with it needs to cover PCB with polyurethane. Not just regular polyurethane, but - you know - with low outgassing in vacuum.
Funny looking, abstract pictures, anyway!
OCTOBER 02, 2013 12:46 PM Tech experiment - 3D printing metal parts in conditions similar to Lunar surface
Technological experiment on the way to 3D printing metal parts on a lunar surface.
Direct Metal Evaporation And Condensation method.
- lunar regolith consists with some, non zero amount of metals;
- extraction of different metals, can be done by applying different temperatures;
- vacuum conditions allow to do this with precision;
- Direct Metal Evaporation will be done inside evaporation chamber directly from a lunar regolith, or from already extracted metals;
- Condensation of the evaporated metal can be done on even surface with temperature up to 200C;
- Evaporation chamber can be positioned by applying the 3D printing technique;
Other technique - condensation surface can be a cavity formed by applying parts to a surface, and evaporation chamber could be fixed till a moment when metal will fill up mold's cavity.
Well, it is slow, but it can be precise, and in a case of remote controlled from the earth time is not critical.
Promising part of the story - on the Earth and at zero-gravity the same technique allows to 3D print parts with better precision than existing technologies.
ON MARCH 14, 2013 05:13 PM Aluminum, again.
With full interaction 27g Al (1 mol) with H2O to form the amorphous Al(OH)3 and H2 by reaction produces 418 kJ of heat. According to calculations by the stoichiometric equation of the chemical reaction for the complete oxidation of 27g (1 mol) of aluminum requires 54g (3 mol) of H2O, with proportion mass of water to the mass of aluminum in 2 times: H2O: Al = 54:27 = 2 : 1: reaction:
2Al+6H2O3 = 2Al(OH)3 + 3H2
2Al + 3H2O = Al2O3 + 3H2
Released at the same time the amount of heat, in the absence of cooling, it is enough to heat the reaction product to a temperature of 2300°C. (based on in
On http://altinfoyg.ru/index.php/rashot/rachotidei/pva.html for comparison - 1kg of aluminum can give 0.11kr of hydrogen with volume 1.24m3 and it is equivalent of a (to compare with gasoline 46mJ/kg) 0.296kg of gasoline. All this articles was about methods how to produce hydrogen using fine aluminum and the water.
Interesting table on page 103 of
http://www.duskyrobin.com/tpu/2007-01-00025.pdf Introducing more water makes process more controllable.
Victor can you check (just curious!). If, instead of H2O, it is mixture of 50%H2O and 50%H2O2 (or may be in another proportion), than: 2H2O2 = 2H2O + O2, and 2Al + 3H2O = Al2O3 + 3H2, and combustion of hydrogen and oxygen also adds released energy. Under normal temperature all components are stable (well, some sort of for H2O2), but if cylinder shaped piece of aluminum will be ignited and mixture will be delivered to a place of burning via cooling channels(inside aluminum cylinder). Then process of burning can be controllable (ignore Ignition problem for now). Where I am wrong?
January 04, 2013 AL2O3, SIO2.
Thanks Boris, in vacuum under temperature Ti2O3 on C surface will be perfectly react with outcome of Ti and CO. Layer of Ti can be formed on top of layer of a C (carbon particles, nanotubes, graphene, just name it). Question how to recycle C – as a first task to catch CO, and second question is to separate CO (as I understand that can be done by chlorella – living creature does it perfectly).
And thanks for tip how to make experiments – Clay is Al2O3 + SiO2 — needs to grind to smallest as possible particles. Dried as much as possible. Place dust into a vacuum chamber and try to separate by electrostatics. Low grade of vacuum (1mm) actually will help to charge dust particle. 6 time bigger gravitation force can be compensated. If separation can be achieved – well, it will be good.
December 28, 2012 ALUMINUM. 3D PRINTING.
Thanks, V. Existing, formulas about aluminum extraction process in vacuum and 1/6 earth gravity.
1. Conductive aluminum surface as forming layer for 3D printing part.
2. Al2O3 distributed by electrostatic on top of forming layer.
3. K3ALF6 as a catalyst, distributed by PVD (physical vapor deposition) precisely on a place of a next slice of a printed part.
4. Beam of electrons on the same square area: Al3+ + 3 e−-> 2Al ; O2− - 2 e−-> O ; K3ALF6 evaporates and can be reused.
In vacuum do no need for a carbon electrode – oxygen will be separated without chemical reaction. Also electrical current in vacuum better be done by emitted electrons. Surface of particles are big for unit mass. In 1/6 gravity different fractions does not separates properly, but it will be layer of Al2O3 , isn’t it? Is it possible to reuse K3ALF6? How to collect O2 effectively?
Well, bicycle as it is. Legend from “Historia naturalis” about Tiberius and goldsmith, brought imperator “silver” looking, light, metal’s plate. On imperator’s question: “How did you make it?” Inventor replied: “From clay.” On next question: “Who else does know the process?” Inventor proudly said: “Only Me and Gods”. It was a mistake, to protect his recently investments in silver, imperator ordered to cut of inventor’s head. Nice, unconfirmed story was, until couple years ago some students got aluminum by technology and chemical components available 2000 years ago only. Again, bicycle’s invention is a bicycle invention. Needs to do this on The Moon, not on the earth! Anyway we do not know investments portfolio of other people.
What equipment will be needed to make such experiments?
December 18, 2012 POSSIBLE SCIENTIFIC EXPERIMENT?
Well, Victor – you right, absolutely - two visible way today – in 2000 was experiments to make Al from Al2O3 in hydrogen plasma
(in some blog reference to UDK 541.14
http://hbar.phys.msu.ru/gorm/forum/index.php?t=msg&th=2433&goto=50817&S=8dc2fbb39a516315e8538348f84b2e64#msg_50817 experiments was done in Krasnoiarsk) , and in 2006 was theoretical study on formula 2Al2O3+3C=4AL+3CO2 (http://www.itp.nsc.ru/Laboratory/LAB_2_1/papers/5.pdf ) again in plasma, was done estimates: 12-14 kWt for 1kg of aluminum at 2400K temperature. Both methods require ether hydrogen or carbon. Carbon is preferable to bring from earth. In second method some amount of a carbon react with aluminum and creates Al4C3, that will require carbon extraction from carbide. Second way requires less energy. Recycle CO2-> C + O2 also will be needed. What do you think ?– can we formulate the real task to investigate instead of just bla-bla - “How to restore aluminum from 2Al2O3
-> 4Al +3O2 under vacuum conditions and lunar environment”, or to forget all this for a first stage and to try separation of Al metal from a lunar dust (some amount already present in moon rock's samples).
Experiment in that case can involve extraction, by static, Al particles, and distribute it to collector to form a wire, then evaporation of the formed wire can create on a concave (or flat, or prism formed) surface some reflector mirror. Simple, light and effective experiment (instead of bringing laser reflector or optical device from the earth will be possible to print it on the moon surface).
December 07, 2012 BLA-BLA-BLA CONTINUES.
Victor – ...With 3D printing on the moon first step will be to separate fractions of a lunar dust. For such porpoise can be used low gravity, vacuum conditions and old vacuum tubes technology. Cathode's material under the heat (as it was in tubes) emits electrons. Anode on some distance from cathode, over regolith (I believe long time ago was an idea to use cathode-anode as a solar battery and theoretical efficiency was pretty high, and heavy) accelerates electrons and part of electrons beamed to a surface of regolith, after some period of charging, charging process stopped, and another plate (charges negatively) placed over regolith, acting as a capacitor’s plate (all of this is from 10 grade physics’ practice book, I believe). Depend of a voltage on a plate, smaller fractions of duct will levitates from a surface, and distributes by weight vertically. Last step - another positive charge applying by tore shaped collector will discharge particles of regolith. Lowing or elevating collector (or by changing voltage of the “capacitor” plate - preferably) will select different fractions. Actually it does not matter how to harvest fraction - static charges, and known formulas can apply. If some fraction will be suitable to make practical object (glass will be first to try) the same principle can apply to a way of delivery dust particle to a surface of printing layers (it will be less mechanical parts in 3D printer).
Surprisingly some of old “school’s” physics bring modern interests – for example charged, same sign, 0.1-100 micron particles, in some conditions can attract each other instead of commonly believed action.
Compact version of useful formulas are in:
Effects on charged dust particles on Moon -
Effects on charged dust particles on equipment:
Plasma with injected 5-60 mkm particles:
Despite of your “contra” about complication of metallurgy process on the moon – and you correct point that this is not our priority today - it is known that aluminum is like “accumulator”, it accumulates energy. Circle – (a) day time producing Al from Al2O3 and (b) night time producing from Fe2O3 +2Al -> heat + 2Fe0 + Al2O3 solves a problem - technological process can work all time without nuclear source.
Surpluses oxygen with aluminum by itself is perfect solid (Al) + liquid (O2) rocket’s fuel+oxidizer.
Can you answer me how that aluminothermic reaction will work not on a tank’s plates welding but on a kainda micro-level – in vacuum, 25 -50 micron size Al and similar size Fe2O3 intersect each other at specific point where controlled heat can apply? It will be nice to make such experiment, today on earth, in big vacuum chamber – but no time, – can you answer what it will be at least theoretically?
And with 3d printing - look what did Markus Kauser :
December 06, 2012 FOR 3D PRINTING.
OK, Victor - in Lunar soil samples:
Plagioclase 30%-35% compositions NaAlSi3O8 to CaAl2Si2O8 , melting point 1100—1550 °C.
Pyroxenes 54%-60% usually for earth that is formula XY(Si,Al)2O6 (X = calcium, sodium, iron+2 , magnesium, rarely zinc, lithium; Y = in smaller size chromium, aluminium, manganese, scandium, titanium, vanadium, iron+2), with melting point 1300°C.
Olivine 3%-8% formula (Mg,Fe)2SiO4 melting point Mg2SiO4 = 1897°C.
Ilmenite (absent in Lunar highland areas) 18%-2% formula (FeTiO3). Melting point 1400°C.
I understand that to get Ti, Fe, or Al from oxides needs to do all chemical reaction. And standard way does not work, no CO, no H2, no C, no H2O. To get Iron from Fe2O3 it is possible to use Aluminum: Fe+32O3 +2Al -> 2Fe0 + Al2O3, and not sure about Ti. Looks like way to start will be Aluminum, with molten oxide electrolysis (it is 1200C) - will requare a lot of electrisity - but side effect – it will be 40% of the oxygen !
http://en.wikipedia.org/wiki/File:Moon_vs_earth_composition.svg . I am not talking about reaction like Fe+32O3 +2Al it surplus heat at night time!
With 3D printing on the moon first step will be to separate fractions of a lunar dust.
ON NOVEMBER 16, 2012 04:34 PM 3D printed CPUs on the moon?
Well, first processors for IBM S/360 computers was done by interesting
technology, CPU by itself was a BOOK(!), with conductors laminated into a
plastic pages. Current introduced by input inductors around BOOK (sorry CPU)
creates tiny current on output conductors on pages, and that current does all
Yes, cooling was major problem (efficiency) to be resolved.
Yes, to change microcode (operations performed by CPU) needs to open CPU’s
BOOK, remove old pages, and insert new.
Yes, it was difficult to design such computer (USSR for example just copycat
existing pages from S/360), and etc. problems.
But today it is possible to 3D print such BOOK (CPU) as one device from
titanium, debug it, tested it (CPU for example can support system of command of
a specific, exsisting processor) and then simply re-print CPU on the moon.
Yep – speed can be slow. Well, size will be big, but old technology can help to
make self-suntanned base on the Moon. All computers required for the mission
can be built on the moon except initial amount delivered from the earth.
The same can be done for amplifiers devices required for a
communications/input/output units – vacuum and dust on the moon is free,
emissions of electrons works same way under solar radiation (instead of heat)
and old century’s triodes, pentodes are perfect to replicate by current 3D
printing technology. Why tubes? – Well solar radiation can kill electronics,
but tubes will be OK! Story of Kemurdjian's team (Lunokxod-1,2 designer) show
interesting twist about tubes – after Chernobil explosions, on roof of the
reactor to clean radioactive debris was tried different rovers. All advanced
robotics failed in first minutes – and only one was working – on tubes – it was
a rover from Kemurdjian's team.
That’s it for today dusty update.
ON SEPTEMBER 27, 2012 01:11 PM one mold's part left
Mold for left tube holder/longeron:
stepper motor sleeve / ceramic bearing holder.
Extrusion of PVA filament is tricky. Filament needs to keep dry – In Vancouver it is hard – as a result needs to cut “spaghetti” 10-25 m long. Estimation of required length in 3D printing software kind of sketchy. Mistake in manual measurement can ether ruin part or extruder can stop thread's extrusion. Loosing part better then stops – PVA in extruder coagulates if left for a long time under 190C.
Video capture and remote desktop essential in this case – from cellular phone it is possible to do check process remotely. Safety is mandatory also – nobody knows what happen if experimental technology will generate sparks. Pictures in last posts was not captured intentionally but rather as a "side effect" of 3D printing process.
Even with all of printer’s problems it is not comparable with time savings.
ON SEPTEMBER 25, 2012 12:47 PM Frame part. mold 2.
Another part done
ON SEPTEMBER 24, 2012 04:25 PM Molds - funny part.
Funny part of the molds/rover frame creation – first mold was made from alumini – epoxy and carbon sweeter (knotted) of a frame was placed into mold – first (93C) and second (163C) cure was done and after process comes the truth – mold can not be disassembled – all attempts was failed. After some consideration was chosen method for disassembling combined with a drop test (14 floor in downtown Vancouver) strata for the building do not allow to throw from the windows cigarettes butts, but nothing in regulation was about lunar rover. Attempt was made with precaution under cover of the night, mold with carbon part of a frame fly freely – and – mold + frame part survived impact solidly.
Fortunately manager of the building was on vacation.
ON SEPTEMBER 24, 2012 04:00 PM Mold printing
Complicated carbon fiber parts for rover and ground
stations, require complicated molds. Design such molds require quite a time to
be properly designed. As a solution for fast mold design was choose 3D printing
technology with material withstand temperature for a 1 stage cure (93C) of
epoxy and mold dissolvable in water. Material is PVA (in long spaghetti form),
and printer is Mendel Prusa. It takes a time (1 month) to build such printer
mostly because printer is in experimental stage, source code in 3 different
languages, technology require precise temperature control, adjustments for
experimental filaments like PVA is mandatory / complicated, extruders is in
experimental stage too. But after questions with software and temperature
control was sorted out, 3D printing allows to simplify mold design. Now it
takes 5-7 times faster to make suitable mold then when mold was made from
alumini plastic. Alumini plastic actually better suited to work in molds – it can
hold second curing temperature (163C) for epoxy, but saving time is more advantageous
in that case. Another advantage is to have 3D printer at hands – this is allow another
time savings – ordering via online alumini molds can not be done faster then
two weeks cycle.
You can see captured screen of a printer printing
first (base) part of the dissolvable mold –
For sure software (ether java or pyton ) require improvements – estimated time to finish print shows
years to finish task, and who knows! – may be software estimation is right ;-)
ON SEPTEMBER 13, 2012 12:36 PM Mold's creation == material PVA == work in progress
... formula” creates cycles of temperature by itself. Period is 1min 20 sec and period is stable, even after 20 minutes it stay amplitude and period the same.
To repro situation needs to compile firmware (Sprinter) and monitor temperature in ReplicatorG.
That is definitely creates a problem with extruder in case: for PVA stating flow point is 180C, starting coagulation temperature for PVA is 200C.
Setting target temperature to 190 makes extruder jam when temperature drop to 180, and melt flow index = 0. That make pressure inside extruder jump, and small jam created.
On another hand when temperature reach 200 it coagulates PVA on a surface of extruder (that will contribute to a jam in a future).
Firmware with PID enable (I do not know correct name = “#define PIDTEMP 1” uncommented) is not capable to print PVA without jam.
To avoid problem need to find solution ether by releasing extra pressure, or by different algorithm of regulation.
Tried setting HEATER_CHECK_INTERVAL to 50 ms – amplitude of cycle dropped to +-5C, period was same, and I believe this is not because of algorithm as it is – just coincidence – when I debugged formula in spreadsheet – in each interval of time it jumped for one bigger value for heater_duty to a smaller value. With 50ms looks like it just “skipped” some of that jumps. When I tried different interval it just returned to same +-10C.
For a plastic with more stable parameters of melt flow index (PLA/ABS) that problem with temperature regulation in extruder is not big impact – plastic flows in a range of +-10C and index is different but varies not much.
Also checked “regular” temperature control (with PIDTEMP commented out) in this case when temperature reaches 191 it switches off, when it is low then 190 –then it is on. Cycles become shorter, and temperature variation is +-5C.
Then I did experiments with heat absorber (I hold heater by big pliers – good contact and good heat adsorption). PID formula works better then on-off algorithm when there is a flow of a heat to cold pliers, when pliers become hoot (around 60 C – temperature when plastic insulation on pliers did allow to hold it in hands more) then “on-off” started to work better.
Definitely to improve extruder for 3D printer needs to control temperature better then +-5C.
Task by itself is interesting not only for dissolvable mold creation, but also for a temperature control in vacuum when only radiation of a heat can be done for “heat flowing out”.
ON APRIL 05, 2012 02:30 PM Team Plan B, Year 2012. Update. Moon as a platform for a business.