Where have all the crystals gone?

Ivan wrote:I found some tutorials, e.g.
https://youtu.be/Ht5B5th2j-s
https://youtu.be/I7n-uMmJevM

BR Ivan

I liked the easiflow tutorial.
I wonder if he made the moulds?

BR Harry

I found some tutorials, e.g.
https://youtu.be/Ht5B5th2j-s
https://youtu.be/I7n-uMmJevM

BR Ivan

That is interesting Ivan.

Using a silicon mould for plastics. Seems technology long forgotten. Also use plaster-of-paris to make moulds. I once made som UK 50p coins using solder ingots and plaster-of-paris.

I needed a minimum about 5cm of head to give a gravity pressure, otherwise the molten metal did not go into sharp corners. But my coins looked EXACTLY the same as real ones. The only difference was when you dropped them. Real ones would ring with a "chinnnnnnggggggg" but mine only gave out a pitiful thuddd. It was only an educational exercise and the counterfeit coins were never used (they cost more than the coin the replicated ).

BR Harry - EA/SM0VPO

Thanks Ivan.
I have seen examples of making copies this way on Youtube movies, but I never did it myself.
But as Harry already mentioned, it is always the 'pin' that breaks.
I think it is the easiest solution to drill a little hole and insert a new metal pin.
The problem is that microphone people are always very critical...
"Ooh, it is metal now, it looks different!". Yes, but the advantage is that now it will never break again!

Hi Ruud,
3D printing of anything is trendy, but there are other, "old-fashioned" methods of replicating plastic details. It should be possible e.g. to press an undamaged part into fresh mixture of silicon rubber. After the rubber cures, you would get a mould and you could cast the parts from epoxy or polyester resin repeatedly. The necessary material (silicon and resin) are usually sold in shops for plastic modellers or decorative arts.

BR Ivan OK1SIP

Hi Ruud,
Yes, to print with a 16um resolution is VERY fine. The "normal" price-range printers have a nozzel diameter of 0.4mm, and at best can print in 0.1mm layers.
Also, to achieve 0.1mm you need a printer with a heated bed so that the layers do not cool too quickly so the next layer will stick.

0.016mm I believe is much more specialised. Perhaps it is because i have not looked. Maybe there is a much more fine standard nozzle I could use?

But i have given you the benefit of my limited experience. You could confirm this by posting questions on one of the 3D forums.

BR Harry - EA/SM0VPO

Hi again Ruud,
Thank you for the picture.
If this is the sort of thing you wish to make with 3D then I believe you will be very disappointed.

1 - 3D printed items using PLA are really weak, and they are easily broken between the print layers. If you were to use nylon or other materials then the printer could cost more, you would need more experience and/or money.

2 - 3D printouts are great for "large and clumsy", such as antenna/balun feed components on Yagis, mounting brackets, and all the toys and trinkets you see on the web.

3 - 3D printers cannot pring plastic "in mid-air". There must always be plastic under every protrusion or sticky-out bit. the item in the photo looks both small/fragile and would need support structures.If you wanted to print an inverted pyramid then you can only have an out-going surface from 40' from the vertical, otherwise plastic will be squirted into mid-air.

Please remember that I am still a novice 3D enthusiast, and perhaps others can give you much better advice. But now that I see whqat you are expecting I am pretty sure that you would be disapointed and feel the printer is a waste of money, unless you have may other larger projects.

The item in your picture I would print by rotating the left-hand picture 90' to the right, and leave a hole for the little tit that sticks out. Then I would glue in there something like stainless steel VHF antenna-wire (or thin welding rod). But if your problem is that the little tits are the bits that break off in the first place, then drilling and gluing wire would be a good repair, without the expense of a 3D printer.

But this is just my own opinion and limited experience speaking.

Very best regards from harry - EA/SM0VPO

Hello Harry,

Thank you very much for your detailed answer!
You are a very busy man!
As with all software: you have to get used to it...
That was also my experience when I started designing PCB's on the computer, many years ago.
I tried different programs and to my surprise, I found that some very well known and highly respected design applications were 'impossible' for me to work with.
For a long time I used Layo1 (a Dutch development, in DOS!), but later they moved to the Windows platform.
That version was less intuitive for me, so I switched to Sprint PCB design.
That works well and has no restrictions I am aware of. It can also generate the Gerber files if I need to have a larger number of PCB's produced by our Chinese friends!

The reason I have become interested in 3D printing is that as you may know, I do a lot of microphone repairs.
The 'world famous' Neumann U87 microphones have switches with pins that easily break.
Unfortunately, Neumann does not have those switches available as a spare part.
The only alternative you have is to buy a complete 'switch and capsule mounting assembly', at a ridiculous price!
So I had the idea that it might be possible to produce these parts with a 3D printer.
Now the only dilemma is: is it worth the money and time investment to get this process under control?
I suppose I have to dig a bit further in on this subject. Maybe have a look at some of the applications you suggested.
Here is a picture of the plastic parts with the 'pins' that always break:



Thanks again and greetings from The Netherlands!

Hi Ruud,
Firstly, I apologize for the delay responding but this past two months have been very hectic for me. I have basically spent 9 weeks travelling, repairing, cleaning and fixing two home for selling. The house in Spain also needs a lot of maintenance, and would you believe, after 5 years we are STILL having to change the ownership names with certain authorities? Here in Spain everythin has to be done on paper, in person, with rubber stamps and things by the right people. Computerisation in Spain is a supplement to paperwork.

3D printing,
The hardest part is to find a 3D drawing program that you like. There are several on the market, and some are free. If youhave any experience with any 3D-capable drafing tool use it. If not then there are several, For example:

https://www.sketchup.com/
SketchUp is a freeware 3D program for creating 3D images. You can create basic shapes, modify them, stick bits on, cut bits out, but I found it to be really limited. If you want something simple to start with then this could be a good start.

https://www.autodesk.com/education/free-software/autocad
This is basically a professional drafting tool. I have used it to draw PCB foils, but I needed a couple of plugins to get it working. It is great for designing houses, but I never used it long enough to become proficient at it.

https://www.autodesk.com/education/free-software/3ds-max
3ds Max is an "industry standard" commercial software used for 3D modeling and 3D animation. It is famous for its powerful modeling tools that enable users to create complex geometries in a clear cut workflow. I used it professionally in multimedia to create animated films. I created nuts/bolts, flanges, rods and built a steel latice radio tower. I put antennas ont he tower, connected them to radio gear in the workshop inside a 3D portacabin. I also created a 3D OC71 transistor, then animated the removal of the case, silicon crap, paint and showed the junction. I then 3D "fried" the transistor.

Whatever you use is really personal choice, but I prefer Autodesk 3D Studio Max because it can be used to create simple 3D shapes, and also has so many complex functions, such as boolian shape addition/subtraction, extruding, lathe, and best of all -really extensive turorials, and many more tutorials online.

OK - so at this stage you can draw 3D shapes.
Export them as *.STL or *.OBJ (ASCII option)

https://ultimaker.com/software/ultimaker-cura
Download a copy of the free CURA "slicer" program. CURA is a simple program to import an STL file, then generage a *.GCODE file, which contains 0.1mm high slices of your 3D model. You will initially need to feed it with a few parameters relevant to you printer, such as nozzle-diameter, temperatures, bed-size, fans on/off, etc. It also displays printing time, length of filament and lets you orient the model on the printer bed. You can also import several models and print all in one print file.

3D printers mostly use *.GCODE commands, which are a bit like the old *.HPG plotter files. The ASCII-format command lines can be edited in notepad, and the commands are basically functional commands meaning NOZZLE-TEMPERATURE, START-FEEDING-PLASTIC, STOP-FEEDING-PLASTIC, MOVE-NOZZL-X-Y-Z_to_X-Y-Z.

Cura was designed for the Ultimaker 3D printer, but it can be used with just about any 3D printer.

Ok, so I have given you some info. Like PCB programs, there are loads that I don't get on with. Autodesk 3DS MAX and CURA are the only software tools I use, and I can do just about anything with them.

I do hope I am forgiven for mey absence.

BR Harry - EA/SM0VPO

Hi Harry,

A bit off topic, but I know that you have been very busy with 3D printing.
How difficult is it to start with 3D printing?
I am a complete idiot when it comes to 3D modeling, but sometimes I have a feeling that it could be very useful if I could 3D print certain objects.
Could you recommend a good 3D design application?
Would be very interested to read about your first steps in 3D printing!

Best regards from The Netherlands!

Hi Dave.
I have got the auto-necking enabled. Now I am getting really impressed with the program.
Necking - another new word for me.

In my lunch break today I started re-creating a few of my existing projects.

Yes, lots of things are disappearing these days. That's why I find the 3D printer so useful.

Very best regards fro Harry - SM0VPO (EA/SM0VPO)

Tracking between IC pins, use the largest track you can get away with, also ensure 'auto necking' is enabled (hi lighted), this is the 5th icon from the top right.

I always try to avoid routing through pins if at all possible, I prefer routing it through the IC... say from top to bottom,  if I can't do this I've used links under the IC seems to be my favourite..., "don't tell anyone"...! Not so easy with SMD chips.

It didn't take me long to 'get the knack' of the program, I've made through holes and SMD boards, but not double sided boards although I have used them for ground planes.

The formers are great, thanks. I've been playing about with one getting idea of the turns and inductance requirements. 'Ally' chassis that's something else that seems to have disappeared what  is the world coming to?

Dave

Hi Dave,
I also had a bad experience with Aliexpress. I bought 2000 voltage regulator chips that didn't work, and a batch of panel meters that were simply put in a plastic bag and sent in the ordinary post. Naturally there were moosed to unrecognisability.

But on the whole, I have had a lot of successes and very few failures.

Today I do not buy from China. Sweden have imposed a China-tax, and imports from China are now subject to duty from the first crown. In effect, a $10 item will cost me another $20 to get it in the country. This is to encourage people to buy locally.

I have only made a start with the program. One thing I am having difficulty with is routing a track between the legs of an IC. At the moment I am building a little R/C project and I will need to start making PCBs for it.

How were the formers? Sorry they were a bit crude. I changed to yellow filament and the quality suddenly improved :-)

BR Harry - SM0VPO

Hi Harry,
I had bad experience with Aliexpress, ordered some panel meters, the numbers on the dial were all over the place and looked as though they'd been stamped by a John Bull printing outfit..... remember em', some numbers were sitting on their sides, in the bin they went, I should have kept them for amusement.

Got a ceramic resonator working merrily away at the moment, was hoping to put a Murata ceramic 455Khz  ssb filters to good use on 160 and possibly 80Mtrs, seems pretty stable compared to using a LC..... I hate miniature RFC's and plastic trimmers in oscillators, they're just not up to it even at these low frequencies.

Built a 9Mhz carrier oscillator using crystal's and it had a peculiar drift, it go up in frequency and down again a few times before settling down a few minutes and start off again, maybe some 20 to 30Hz or so might have been a bit more, quite a while ago now the cause was those plastic trimmers I used, a 5mm ceramic cured the 'wobble'.

Hope you are enjoying that program. 


Dave.

Hi Dave,
You are right - they seem to have disappeared from the web. All I can find is ceramic resonators and filters :-)

https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190319122741&SearchText=455kHz

I will have a look at my stocks at home the next time I go to Spain, and let you know. But twill be a few weeks before I go there.

I think I have some 10.245MHz and 11.155MHz used for converting 455 kHz to 10.7 MHz. I need to get my hands on those, too.

BR Harry - SM0VPO and EA/SM0VPO

Anyone know a source of crystals for a 455Khz SSB filter, they need to be around 453.5 & 456.5Khz for carrier generation? I have a couple of HC6, 456 and 454 Khz but can't be pulled far enough.

Dave