Sourcing non-printed parts

General
#1

Lots of people have found different places to source the fastenings (M3 nuts and bolts, for example) in different countries, as well as different places to get hold of the optical parts. This thread tries to be a place where we can collect sourcing information. We should probably tidy it up and put it into the handbook, but that’s harder for lots of people to edit and discuss, so let’s share information here first.

There is currently a page in the handbook for sourcing non-printed parts, but it’s quite sparse.

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#2

Some relevant Issues:




#3

That is a good idea. I spent a lot of time and money on sourcing the parts. Ended up buying screws etc on Amazon.

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#4

I’ve finally ordered some stock of screws and o rings, so hopefully very soon OpenFlexure Industries will be able to offer kits (in the UK at least) of the non-printed stuff. I’m just waiting on condenser lenses and LED cables now. If you didn’t mind sharing what you bought and from where, I’m sure it would be really useful to others here.

#5

Here is my sourcing and I will update this later :

PMMA LED lens Diameter 13mm Height 5.0mm Plano Convex (Aliexpress) - not tested yet - 0.23$/pc (waiting delivery)

20pcs 342 (ODThickness) Green Fluorine Rubber O Ring (Aliexpress) - Great and do the job well - 6.8$ 20 pcs

Tube lens Diameter 12.7MM Focal Length 50MM Achromatic Double Lens (Aliexpress) - Not tested yet (waiting delivery) - I bought mine 18$/pc but price fluctuate and tooday the lens is 25$/pc
Tube lens on Thorlab direct link - work great - 50€/pc (but in UK and fast delivery in France)

Beam slitter
From Comar, but didnt order yet here the link I was thinking of [25 BV 16] 25x16mm 450-700nm (visible) 50% - £22.75
From Aliexpress : Just a search Link

For nuts and screws in France I use for years now Bricovis

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#6

Hi everybody,

It’s a great idea because when you begin the build you are a little lost, even more when you are a complete beginner in optics domain (I build the microscope for my daughter).
I’m in France.

I have ordered the Tube lens from Thorlabs as indicated (but they ask a lot of official papers to be filled). Very expensive with VAT + shipping : 80€

For the Nitrile rubbers, I have found these ones on Amazon UK (pack of 50) : https://www.amazon.co.uk/gp/product/B07FH85GDL/
I hope that’s the good ones.

Maybe a group purchase would help to get some reduced prices. Kits would also be very helpful.

Regards
David

#7

I also paid about 80 euro for the tube lens from Thorlabs. Was offered 200 pcs for 3 USD/pcs from a Chinese producer on Alibaba. So it looks like significant savings should be possible through a group purchase.

#8

Is $3/piece for achromatic lenses, or just planoconvex singlets? I think achromats probably are worth spending a little more on, because the early versions of the microscope definitely did suffer from using singlet lenses. Of course, everyone’s price/quality tradeoff will be slightly different…

#9

Not sure, I just sent over the specifications as it is on the website but did not consider it seriously as I do not need 200 pcs for the moment. I just notice that it would be much cheaper than the one I bought from Thorslab. But I agree, it might be worth paying more for better quality.

#10

I too am also still waiting on 20 x pmma lens 5mm from Ali Express :frowning: I fear a trade war between US and China has my order siting in a container ship somewhere.

I have been able to take tiled picture sets and use Microsoft Image Composite Editor to stitch them together on the lower resolution optics, my understanding is that this PMMA lens will help add to the contrast and potentially have better quality stitched together pictures. The white LED alone seems to have been enough to lighten the picture. I am really curious if I am even missing out on some quality without this lens.

Given that we now seem to have a supply chain problem with the PMMA objective lenses, I am interested in finding an alternative. Adafruit has much larger 40mm lenses that just seems crazy big. Perhaps 2 LEDs and/or a wider hole?

Stitching images
#11

2 LEDs is tricky, because it means the illumination isn’t uniform any more; arranging several LEDs to cover a wider area (or even using a matrix of LEDs like Adafruit sell) is an option, and indeed people have published some cool results making synthetic images by illuminating one LED at a time and combining all the resulting images.

The lens in the illumination does two important things:

  1. it concentrates the light from the LED into an area just a little bit bigger than the area you’re imaging, which means
    a. you improve contrast because there’s less light hitting the objective from outside the area you’re imaging
    b. you improve brightness because you’re not wasting much light
  2. It increases the numerical aperture of the illumination, i.e. the light converges on the imaging area from a larger range of angles.

The lens means you’re illuminating an area around 1mm across - so it’s concentrating the light by a factor of hundreds or more. So just adding a few more LEDs will improve brightness but not by anywhere near as much. However, if you have a fairly bright LED, brightness is often not what limits you, it’s stray light (which you really can’t fix without a lens) and numerical aperture. You can fix the numerical aperture problem by using a diffuser instead of a lens - try sticking some white electrical tape over the aperture where the lens should go. It will hurt brightness even more, but should improve image quality if you have a bright enough LED to start with. You’ll want the condenser fairly close to the sample.

#12

I just found this one which seems to be the same tube lens but cheaper https://www.aliexpress.com/item/1005001369600847.html?spm=a2g0o.productlist.0.0.329b3359D0iwWj&algo_pvid=b37d29e5-5c77-4d6f-bdc7-149d8dd2b98a&algo_expid=b37d29e5-5c77-4d6f-bdc7-149d8dd2b98a-1&btsid=0b0a187915998984428141743ed63a&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

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#13

I got the tube lens, it seems to work fine.

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#14

Hey folks,

I have a recommendation for a source for inexpensive optical components: Surplus Shed

Hobby astronomers and tinkerers in the US have relied on Surplus Shed for many years to provide high quality optical components on the cheap. I intend to use the following items to build a reflected light version of the openflexure microscope for metallography. I will let folks know how these work after I finish the build, but I thought I would share this now in case it’s useful to others.

For the beamsplitter, I am going to use this: https://www.surplusshed.com/pages/item/L14550.html
I will cut off whatever I need using a diamond scoring tool for cutting glass.

For the achromatic doublet lens, I will use this: https://www.surplusshed.com/pages/item/L3955.html
These are very high quality anti-reflection coated lenses which are old stock from Edmund Scientific. For $4.50 you really cannot do much better than these lenses. Evidently they have a large quantity of them, so we could buy a bunch and supply half the planet with microscopes :slight_smile: One issue is that the openflexure microscope build notes specify using a 12.7mm x 50mm fl lens, and these are 13mm x 49mm fl. There must be a way to workaround the slightly different specs. Maybe it won’t even matter? I will open up another discussion to talk about modifying the optics module to account for different lenses.

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#15

Hi @atbalogh that is an amazing site! I had not seen it before - I wonder if they ship to the UK and whether the faff of customs etc. outweighs the impressive pricing…

It is definitely possible to customise the optics module for different lenses, though as you mention I suspect the difference between 12.7 and 13mm is not likely to matter (in fact, it’s quite common for 12.7mm lenses to be labelled as 13mm; half-inch is quite a common size). A 1mm change in focal length is also probably not that big a deal - but as part of the appeal of a parametric CAD design is the ability to do precisely this sort of tweaking, it seems like a good opportunity to document the optical design a bit better.

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#16

Hey @r.w.bowman , Surplus Shed ships within the continental US for a $6 flat fee regardless of weight. They also ship internationally. In my experience shipping packages to the UK, the cost starts around $25. I think this would certainly be worth the cost per lens if a large order were placed.

#17

Hey @atbalogh did that beamsplitter work out for you? I’m thinking of putting in an order soon, as it looks good. Thanks!

#18

Hi, I’m a student and new to microscopy and I am trying to order parts but I am not sure which objectives to get.

I have looked at this on aliexpress which seems to be Plan

and this one that seems to not be Plan
and https://www.aliexpress.com/item/32913301769.html?spm=a2g0o.cart.0.0.65c73c00RT6nQq&mp=1

Can someone in here confirm that the objectives I found can work with the Openflexure microscope or recommend one from aliexpress? I plan to mostly look for organisms i water samples from the sea, and wonder if it is better to go with just one 10X Plan objective or to get both the 10X and the 40X that are not Plan?

Best Regards

#19

I’m new here and based near Norwich, in the U.K.
I’ve printed my parts for my first basic microscope build, I’ve just ordered these 13mm diameter 0.5 mm condenser lenses. I’m only likely to need a small handful but the minimum order quantity was 100. So I’ll have quite a few spare if anyone needs helping out.

Secondly I’ve managed to find most of the hardware in the spares I got with my Prusa kit. But for bulk buying I’ve one or two contacts in the fastener (the engineering name for nuts bolts and screws) business who I’ll ask about parts for mail order.

Lastly I’m wondering if it’s possible to use lenses from those Russian microscopes used in schools back in the 90s. Once I’ve got the basic microscope working I want to build a higher resolution one. And those ex school Russian ones are very cheap on EBay.

I’ve not used a microscope since the 1970s when I was at polytechnic reading Zoology. So I’m going to have fun both building and using one,

Regards,

Steve

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#20

Hey, I’m also trying to hunt down some suitable objectives. I think the objectives from both those links would be suitable (they both have the correct 160mm tube length and the RMS thread size). For a 40x objective the openflexure documentation recommends semi-plan or plan, so maybe you don’t need plan for the 10x? At the end of the day you’ll still get an image without plan, so it depends on high much you care about the image quality and the edges being distorted.

What concerns me about those aliexpress links is what sort of quality they are. I tried to find some recommendations from another group that is doing DIY/3D-printed microscopes (UC2 from Germany). They say they’ve “tested” two different sets of aliexpress finite objectives here and
here. Maybe they are OK quality?