Extruder Nozzle Drilling 0.3mm hole

I am currently trying to have a go at making my own hotend with a 0.3mm nozzle opening. However while I can make most of the nozzle with little issue I am having huge problems with the smallest part.

I suppose I am looking for suggestions on drilling out the 0.3mm hole with the 0.3mm drills I have. Have access to a lathe and drill press. Tried it on the lathe and broke one and bent another bit as soon as it made contact with the metal, I am using aluminium. While I have been able to use a lathe for some other simplier projects, this is probably the most complicated item I have attempted to make!

... carbide drills are pretty sensitive too, so make a center cavity with a bigger drill or a graver pin.

Then try to perform a 'pecking drill', with really short smooth contacts with highest possible rpms ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Here is a great demo on drill small holes.

[www.youtube.com]

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Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

I did mine using a Dremel type drill in a pillar mount. And used a drill with a bigger shank

Thanks guys I'll have a go later today

Hi,
I have drilled several hot ends with 0.35mm holes, I use a pedestal drill and extreme care. Use oil on the drill as well.

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[3dprinting4u.wordpress.com]

Having drilled holes down to 0.2mm (or 0.15mm unsuccessfully) on both a Proxxon MF70 CNC mill and an antique Meddings sensitive drill, the best advise is to think tiny amounts of feed and pressure, but keep the speed high - I use 6000 to 12000RPM. Each peck should be around 0.1mm to 0.25mm and take about a second backing off very slightly each peck and withdrawing the bit fully every 4 or 5 pecks.

Another vid:

[www.youtube.com]

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--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

12000 rpm's aren't fast enough for smaller bits than 0.2 - I've milled and drilled holes with 0.3mm carbide and a spindle with 22000 rpm -- and drilled with a 0.1mm (fast?-)steel-bit and 25000 rpm with alcohol cooling.

Experts suggests even higher rpms like 40000, bit such spindles are really expensive

For smaller nozzle diameters I'm drilling with 0.3mm, then either (with aluminium or soft materials) insert a steel wire with the wished diameter and 'compress' the tip, until the hole is small enough ... or I'm simply hammering on the tip, so the hole is closed and drill only the thin closed/compressed part with the smaller drill - this works good for 0.1mm.

For smaller holes than 0.1mm I'm using galvanics for reducig the diameter by coating with nickel or gold ... or insert a fibre with the end-diameter, close the hole completelly and etch the fiber away afterwards. The smallest holes we made with this methode were single microns wide ...

But we made even smaller holes with some ten nanometers in diameter at the GSI in Darmstadt/Germany with accelerated ion-beams and etching the ion-channels to the wished diameter

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Regardin speed my lathe can only reach 2000rpm. Only device that I have that could reach 15k+ is my hobby Dremel type tool - but I don't have a press for it.

@VDX
I like your idea of drilling out a larger hole, compressing it down and re-drilling. For a 0.3mm hole, what would you suggest as a starting size?

... you can start with 0.8 to 0.5 ... it's too relating on the geometry or the tip - thinner walled cones can be 'compressed' easier ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

i would take a centerpunch, set it to a low setting then make a divot where you want, then drill the hole, then file the tip till its level with your build platform.

Drilling really small holes is not so easy.
I was thinking of extruding a copper "tube" to reduce the diameter of the hole, then soldering the tube into a brass nozzle. I have not tried this, so there could be all sorts of reasons why it won't work!

Have a look at my video...(the first one)

[reprap.org]

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Waitaki 3D Printer

In the lathe video what you need to notice is that the drill chuck is perfectly centered on the lathe chuck. You can tell because you don't see the drill bit wobble when entering the hole. Getting you lathe drill chuck perfectly aligned with the spindle like that that can be difficult to do.

Technically, it is not possible to perfectly align the headstock with the tailstock. There is always going to be a certain amount of misalignment.

Center drills solve this problem by bending just enough to drill a circular hole in the material turned in the headstock. The diameter of the hole drilled is a fair indication of the misalignment.

I was taught that the center drill ends up working like an end mill.
The center drill is short so it doesn't flex, and create an off center pilot hole.

Use the lathe,

Start by back drilling the back of your nozzle

Verify your tail stock is on centre

Make 100% sure your face is smooth and has no signs of previous attempts or a centre pip to make the drill wander,

C/ drill with a small centre drill (you only need a pin prick, no more as you want to lose it when you drill through,

Then pop the .3mm drill in a pin chuck if your normal chuck won't hold it,

Up towards top RPM (but not so much you get vibrations,) I've successfully done it at 1800rpm

Lock the tail stock in position, and stiffen up but don't restrict completely the movement of the slide with the slide lock.

Drill her out! slow feed (the slide lock helps this bit), look for the swarf coming out, it not, something is wrong

Drilling the 2mm or so normally required should be done in around 8 or so pecks, when they get drilling they drill nicely,
At 3mm your drilling to 10 x the Diameter of the tool, most tooling suppliers sell drills in 5D, 8D and 10D possibly some 12D if you're lucky to put it into perspective

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