So, how's it done ?

[Arfa Daily]

Number one daughter just bought some MDF letters off the net, to spell out her new son's name. They are about 150 mm tall and I would guess that the MDF is about 15 mm, so they free-stand. The font appears to be Times New Roman, so some quite tight 'spiky' bits on the letters. The cut edges seemed incredibly smooth. Given that they were only £1.70 each, how are these being cut from the MDF sheet ? The two thoughts that I came up with were either a laser cutter, or a CNC machine of some sort with a fine router cutter. Thing is, there is absolutely no sign of any burning, so I think that rules out a laser cutter, and the spikes and angles on the letters are very sharp, which I would have thought would be difficult to achieve even with a very thin rotary cutter. Anybody seen it done, or know what they use ?

Arfa

[Bill Wright]

Do you assign the numbers chronologically or on some other basis?

I have my daughters numbered by a system of reverse demerit. Daughter Number One is the daughter who only comes round here to scrounge electrical appliances and allow her children to feast from my fridge once a week.

Bill

[harry]

Individually pressed into moulds?

[Nightjar]

My guess would be a water jet cutter.

Colin Bignell

[fred]

Garden centres have been selling decorative wall panels in exterior grade m df with fine detail in them. I always understood they were done by laser.

On the other hand a CNC machine would piss through them. Might be a bit slo w but like a washing machine you can walk off and leave it to it.

[Nightjar]

with fine detail in them. I always understood they were done by laser.

but like a washing machine you can walk off and leave it to it.

You can minimise surface burning on MDF by using high pressure air jets to cool the cut, but the cut edges will turn brown. That can be removed with a second sanding operation and is not a problem if the product is to be painted, but a water jet cutter will leave a clean cut from the word go. As you say, a CNC machine would be an alternative, but a water jet cutter would give much better productivity, as well as a lot less waste. Hence my guess that it would most likely be done using a water jet.

Colin Bignell

[Tim+]

Video of wood being cut using a water jet.

Tim

[Gazz]

How many off here have gone on to search how to marry a karcher pressure washer to an old plotter for a DIY water jet machine :)

[Bob Minchin]

My bet would be CNC router. They use spiral cutters which give a very clean cut and no burning or fluff with the right grade of mdf. A have a friend with a machine that just eats up 8x4 sheets from a .dxf file that I send him. Big vacuum bed holds the sheet in place. Thin mdf backer sheet is porous enough to suck down a sheet on top and allow the cutter to cut into the surface slightly. Fascinating to watch if working

- for the first few minutes then you just get on with something else.

[David Hearn]

How would that work with MDF which easily absorbs water and swells if it comes into contact with water?

D

[Nightjar]

...

The water is only a carrier for an abrasive and most of it passes straight through. These people offer a commercial service cutting MDF:

Colin Bignell

[The Medway Handyman]

MDF doesn't like water!

[stuart noble]

Watch the video. Not water as we know it

[Jules Richardson]

I think it's only significant if it's in contact with water for a long time; I rustled up a small water turbine using the stuff a couple of years ago for a science demo (after doing some testing, and after fabricating using acrylic sheet was taking too long) and it's run lots of times for ~15 mins at a time without any signs of swelling.

cheers

Jules