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Machine shopping for a microscopy lab


Disclaimer: I believe that everyone who can hang a picture on the wall can work in a machine shop. However, if you are sloppy, forgetful, or messy, don't do it. Or at least read the manuals and learn safety instructions before you go.

If you are still reading this, you are not easily scared! Welcome to the world of DIY fun and creativity which a machine shop provides. Let's start with the most common myths.

Myth 1. Machine shop is for old-school dudes who like to fix their motorcycles - today one can buy online everything needed for science.
If you can buy everything - you follow mainstream, because your tools are old and popular enough that a company makes money making and selling them. If you hit an unbeaten path, or even make adjustments, you need to invent and make new tools. Of course, you can hire engineers - but research labs are rarely that rich.

Myth 2. Machine shop is a big and expensive enterprise, only big institutes can afford it. 
MS can be as big or small as you make it. I know an old Russian guy who was making custom-made cameras for wildlife photography using a lathe and a mill in his bedroom. If your budget and space are limited, you can fit a decent MS on one large table (more on this later).

Myth 3. One needs a lot of different machines.
One needs to understand which machines are most needed for his/her purposes. Usually this boils down to 2-3 machines used for 90% of the tasks.

Myth 4. Only trained machinists can operate the machines.
Operating basic machines is not more difficult than cooking. Almost anything these days can be learned from youtube.

Now, enough with the myths. Which machines are most useful in a microscopy lab and why?
Most of the time your new gizmo falls into one of these categories:
  • Holders and mounts (for LED, lamp, lens, objective, projector, motor, etc)
  • Adapters (mating parts from different vendors, fitting imperial<->metric, adjusting height/offset from optical axis)
  • Cases, boxes and enclosures (lasers, electronic devices)
  • Heat sinks (lasers, LEDs)
  • Chambers.
Materials. Most of the parts in microscopy lab can be made of plastic or aluminum. Plastic is easier to cut, but it has higher coefficients of linear thermal expansion, so parts made of it expand or contract more due to room temperature variations. This can be a problem in sensitive components like sample holders. Some plastics are more machinable due to their good resistance to high temperatures, for example polycarbonate. Check if the plastic has desired properties before machining from it.

Tolerances. Typical milling, in principle, can be precise up to 25 microns (0.001 inch). However, to achieve and maintain this precision requires high qualification of an operator. Thankfully, tolerances in DIY microscope parts can often be quite permissive (~100 microns, 0.1 mm) which allows simple dudes like us make stuff without special training.

Must-have
 3D printer. The cheapest, fastest and most versatile way of making custom things. 3D print your part if you can - it's a big saver of time and money.
Downsides: relatively low accuracy, rough surface finish, plastics used in consumer-grade printers (ABS and PLA) easily deform at high temperatures. High thermal expansion coefficient of plastic, so microscope parts can drift due to temperature variation in the room.
 Milling machine (mill): drills holes, mills surfaces, and cuts slots/grooves.
Typical use in microscopy lab: drilling holes for custom tap size in Thorlabs breadboards; cutting off unneeded parts, drilling holes for cable routing.

One can also buy a drill press to make holes. However, a mill can do holes and additionally cuts in XYZ directions, so it is a better investment.
 Bandsaw: cuts sheets of plastic or metal, including aluminum breaboards,  pipes, rods and Alu-extrusions.
Indispensable tool for customizing breadboards and making laser enclosures.



Nice-to-have
Sander machine: used for finishing the cut surfaces, making them flatter and closer to the desired dimensions. Very useful and quite cheap machine (typically < $100). If you don't have it, you will spend more time filing your parts by hand.


Laser cutter: computer-controlled cutting of plastic sheets with high accuracy. Great tool for making custom boxes, holders, enclosures from acrylic plastic. Can also engrave your name and logo!
Caution: plastic emits toxic fumes when laser-cut, so a good air ventilation (or hood) required.

Lathe: allows making cylindrical objects, and precisely cut edges of pipes and rods. Used less frequently than mill, but if needed, becomes indispensable.


 CNC Mill: essentially a milling machine with full computer control over XYZ motion. You can make a CAD model, upload it to the CNC computer and (ideally) the machine will do the rest. Get one if your budget allows it.


Budget and considerations
Prices are approximate

3D printers.

Extrusion printers are budget-friendly, materials are relatively cheap and can be purchased from many suppliers. Higher-end printer is preferred is you want to spend more time on science and less on printer debugging.
Example: Ultimaker 2+, €1900

Stereolithography printers use UV-curable resin and give higher precision than extrusion printers. Come at a higher cost and relatively expensive resin.
Example: Formlabs Form 2, €4100

There are a lot of reviews and resources about 3D printers: check 11 things to consider to start with.

Mills.
My favorite. Table-top mills can be very affordable, starting from less than €1000. But don't go too cheap - there are several catches:
  • Heavy is better, so cast iron base is good. If the mill is light-weight, it is more flimsy and prone to vibrations, which reduce accuracy.
  • Cheap mills have looser tolerances, large backlash and, again, vibrations.
  • The more power, the better. Good table-top mills start from about 1 hp (750W) power.
  • If possible, get a machine with digital axis position readouts (DROs) - they simplify precise positioning a lot, being available in high-end machines.
I currently use Holzmann BF16V because it is cheap (€700), compact, and does its job for a buck. However, large backlash and wobbling of the XY table preclude doing any accurate milling. Still, it does 80% of what I want it to do.

If you want accurate milling, invest in a more expensive machine, it will pay off. Expect spending at least $2000 on it. After some research in the Internet, I listed some good options below. Your best bet  depends on your budget, geographical location and, well, fussiness of your institute's purchase department.

In the USA
JET JMD-18, $2300
Shop Fox, $2200

In Germany
Paulimot machines, starting at €1200 (610W) and up.
Optimum Maschinen
Frada Shop, especially BF 25 with 3-axis digital readout, for €2100.
etc..

Note that mills are typically sold bare and require a few extra things: sturdy table, machinist wise, end mills, and center finder. But these things are relatively inexpensive.

Good reviews about purchasing a mill.
Shopping Guide for Best Milling Machines
Tips for buying your first milling machine

If interested in more details, message me @nvladimus and I will cover them in updates.

Happy machining!

Comments

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    Keep Sharing!
    Thank You!

    CNC Bandsaw Machine

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