< Workshop notes

Workshop notes

3D Printing

If you have intermittent extrusion issues, i.e. plastic stops coming from the nozzle for a short while you likely have one of the following issues:
1. Wet filament: Water can cook out of the filament and the vapour interrupts the flow. This is usually accompanied by a popping or sizzling sounds and you can see bubbles form in the extrusion. Solution: Dry your filament, store it in a drybox.
2. Miscalibrated extruder: Your printer is not pushing enough filament into the hotend. The pressure drops during extrusion (especially with a larger nozzle) and flow briefly stops until enough new filament is pushed in to build pressure again: Solution recalibrate your extruder like described in this guide. Basically you command your extruder to move in some length of filament, measure how much it actually moves and update that value. These are the required commands:
```
M503          ; get current extruder steps
M83           ; relative mode 
G1 F100 E180  ; extrude 180 mm, assuming you marked 200mm on the filament
M92 E???      ; update new extruder value
M500          ; save
                    
```
3. Filament not being moved correctly: Your filament might be getting snagged somewhere, like at the ends of the bowden tube or the spool is not moving right. A spool on bearings might start swinging and yank the filament back. Your extruder wheel might be dirty and slips. This is best diagnosed by lightly keeping a finger on the filament as it is being pulled in and checking if you notice stops in movement.
If you start upgrading your printer plan very carefully which 3D printed components you might need before you take the printer aprt.
Wet filament can cause a plethora of issues on a machine that works fine otherwise. New filament is not guaranteed to be dry even when it arrived vaccum sealed and with dessicant. Drying it when new can be helpful sometimes.
If you want to make frying filament quantifiable, weigh the spool before and after drying.

Soldering

When soldering components with a large heat capacity, like 3D printer heated beds or just huge cables, your soldering iron will likely lack the power to effectively solder the component. What happens is that the rate at which the part removes energy from the soldering location is larger than the rate of your soldering iron putting it in. If that happens, take a piece of brass and heat it with a gas torch until it glows red hot. Use this as your soldering iron. The energy delivered by such a piece of metal can be enormous. Extra hint: For more control, mount it to a wooden handle with some thick steel wire that doesn't melt or deform much when heated. Beware of press fitting parts here, since heat exapansion can make parts come loose and somehow hot metal pieces love to fall onto legs in particular.
A dry soldering iron transfers very little heat, especially the pointy kind. Adding any amount of solder immediately increases heat flow significantly, into the parts wetted by the molten solder. By holding a blob of solder against a cold component you will heat it up quickly.
Usually the correct soldering technique is:
1. Have some molten solder on the iron
2. Heat both sides of the joint with the molten solder. Observe how heat transfers into each component by observing when solder wets the part.
3. Feed solder wire into both hot components, not onto the iron or the blob attached to the iron. Often feeding from opposite the iron gives the best joints. If the solder blob on the iron covers the entire inteded joint, feed into it and remove the iron from the solder joint first.

Circuit Planning and Layout

For planning circuits on perfboard or stripboard DIYLC works well.
Laying out circuits on grid paper is a valid option: While you have to restart often if you change things, it's much less hassle than using any planning program.
When transferring a DIYLC stripboard layout to the actual stripboard beware that all holes you made to break stips are mirrored. DIYLC shows all components on one side of the board, while on the real board the stripes are on the opposite side of the components!
There seems to be no material online about heuristics how to layout a prototype board. Here are some rules I developed:

For both perfboard and stripboard, try to route one voltage and one ground rail somewhere on the perimiter, so every component can be attached to it easily. Sometimes it makes sense to split a rail though.
Test how many holes a component spans. Some have odd pitches and might need to be mounted diagonally.
While it feels inelegant, the grid layout is not sacred: You can always angle components. Long parts, like resistors can be mounted vertically and connect adjacent holes.
When looking at a circuit diagram dont't copy wires 1:1. Think about all connections made by a wire as a single node: For example if two components are shown to need a connection to ground, you can just connect part A's ground to part B's ground since it's functionally the same.
Print your circuit diagram or open it in a paint tool to mark all connections made on the board: Measure on the board and then highlight the connection in the diagram. This allows you to find missing connections quite reliably. Don't go from the schematic to the board, as this makes it simple to assume a connection without actually measuring it.
Chose the size and shape of your board based on how the circuit naturally "falls into place". Do not optimize for minimal size prematurely, since a compact circuit is much harder to make and test. Only optimize for size if your project really requires it, as an oversized board allows you to add stuff later as requirements change.
Always socket your ICs unless you expect extreme vibration or G-loading.
Decide early how to supply power to the board and make the connector a central part. Hacking it in later often messes with the layout.
Avoid connecting your bench power supply with alligator clips to loose cables. The risk of short circuits is very high and makes testing annoying. Insted, build a dedicated wire for your power supply to your board and keep it around for later. For example cable shoes to barrel jacks.

Lathework

If you encounter chatter, first tighten down everything you can to minimize movement of the tool. If that doesn't help, use more lubrication, which can make difficult cuts doable. If that still doesn't help, you can flip your tool upside down and run your lathe backwards. If this still doesn't work, reconsider what you are doing, since at this point you are approaching the mechanical limits of your machine.
A quick change toolholder is one of the best first upgrades for any small lathe.

Mini Mills

Tiny mills will chatter since they simply don't have the mass to withstand the cutting forces involved.
Hacksaws and files will often outperform a very small mill. Roughing a piece by hand and finishing it in the mill is often faster and cheaper than doing all by machine.
Cheap endmills will make easy cuts utterly impossible, quality endmills will make them nice.
Proper lubrication can make a significant difference in quality of cut and noise level.
Keep track of the heat building up in your mill. Small machines are often not well cooled and you can overheat a motor or spindle while you're in a flow of cuts.
If you encounter a lot of chatter, check if locking out all unneeded axes helps. Sometimes an extra clamp can reinforce a flimsy clamping screw.
Breaking through a piece of metal with a drill or endmill is one of the more challending things to do on a small mill. Whenever possible have something behind where the tool will break through. Don't rely on being able to hold the quill against the pulling force.
When drilling into a long bar there is a significant risk of it suddenly being pulled from the vise and rising up the drill. Once it reaches the end it will swing around and might hit you right in the face or eyes. Bars are hard to hold flat in vises. The extra effort of clamping it down is often worth it. If you can't, a faceshield is recommended.

Safety

Eye protection is non-negotiable. Look up eye injuries on an image search of your choice if you disagree. Eyes heal poorly and getting materials into your eye that can't be seen on X-ray or are not magnetic is especially horrible.
Gloves can be necessary in some situations and a risk in others. Spinning tools can catch gloves and rip of a hand, fingers or the skin off the bones of your hand. For example, lathes and gloves do not mix.
When you or a part of you enter a machine designed to cut wood or metal, you stop being a person and rapidly start being lubricant. Treat your machines accordingly, even if they seem tiny compared to industrial tools.
Anything that is hot and sticky, for example hot glue, some solder fluxes, resins or cutting oil will burn you deeply since it lingers in one place, continuously dumping heat. Napalm was designed to be sticky on purpose.
Steam, even in small amounts, can rapidly burn you, since it delivers four times as much energy as boiling water.
Burns take a while to start hurting. Instead of thinking if you need to cool the burn site, immediately cool it and keep doing so longer than you think is necessary. Like in metal, the heat dumped into your tissue keeps creeping deeper, causing more damage. Cooling minimizes this, so better overdo it.
When soldering with flux core solder wire, the flux can cook of and fling itself 20cm to 30cm. Wear eye protection, since the hot resin hurts a lot and the cool resin forms a small granule which can attach to your eyeball.
Avoid setting up "traps", like open knives, pointy objects on chairs or (my favorite) hand drills standing upright with a sharp drill in a frequently used path. In the heat of building something you will forget about these things. You either need to always keep these in mind or you will hurt yourself. The extra second to store them safely or position them more safely can save you days or months of recovery form an unnecessary injury.
Whenever you see or smell smoke coming from a workpiece, either use a respirator or fume extraction (or both). Air out your workspace after any emission of particles or volatile compounds. Chemical damage accumulates but it is easy to think "just this once" every time you breathe "just a bit" of soldering fumes.
When working with acids (e.g. to remove oxidation from metals) avoid smelling them directly or keeping your face above the containter. Especially when placing hot metal into acid, vapours form and they can quickly attack your eyes or nose. Acetic and citric acid in high enough concentrations can be quite corrosive, despite not feeling as scary as other substances.
Every time you push any sharp tool towards yourself you almost guarantee a hand injury which will put your project on hold or at least reduce your dexterity for several days. Even if you are fully aware of the risk, once you slip it is unlikely you can stop the cutting motion in time.
When working with lasers or any IR or UV source, you can damage your eyes instantly, or slowly depending on the emission type. Always cover the source, always wear protective eyewear which you have either measured yourself to block the radiation, or is certified to do so. Before working with IR or UV make sure you have an adequate sensor to detect emissions. By definition you cannot rely on your senses to warn you about damage occuring from these imperceptible sources, until it is too late. Electric arcs generally emit strong UV radiation, so be wary while welding or producing arcs in any other way.

General Ideas

Organization is a process not an event.
Organization can only be achieved if every item has a "home", i.e. a fixed place. All objects that don't have a home will invariable become nomadic between whatever free horizontal surfaces exist.
Try to establish first order accessability for tools you frequently use. That means the tool should be accessible without having to move anything else to get to it. In a space-constrained workshop you likely can't provide this for all tools, so a selection will have to be made.

Misc

Hot glue gets a bad reputation from a lot of misuse. It is however a legitimate way to make connections you can correct and remove later, as well as securing connectors in high vibration environments.
Tweezers can be modified by chopping off the fine tip and grinding a coarser one. Modified like this you can grip with much more force, for example for hard soldering tasks.
Build a set of connectors for your benchtop power supply. For example if you have JST connectors of various pitches or barrel jacks, attach some loose wires and keep them in storage. You'll be able to power many devices without a janky wire job.