(43) Perhaps CNC builders do need to remind themselves every now and again.

 

(44) A new nameplate for my AVO Douglas linear coil winder.

 

(45) Some notices are made just for fun.

 

(46) This panel was engraved and then the holes and profile were cut with the same 1mm endmill using the same G-Code file, produced with G-Simple.

 

(47) This type of engraving is very effective but is quite time consuming to produce.

 

(48) Different type of engraving. This was produced using a simple, vibrating, impact engraver (ideal for harder metals such as stainless steel). Shown here are some of the typefaces available with the Mach3 engraving wizard.

 

 

 

 

CNC machines, like Tweakie, are well suited to engraving but the first snag encountered is the lack of single stroke or stick fonts to use. Microsoft, in its wisdom, has settled on closed type fonts (this is where the start and finish of the line forming each character occurs in the same place - each character is a closed loop) which means that instead of the letters looking like this:- EXAMPLE they look like this :-

 

These closed type fonts are fine in many applications, especially when engraving large characters, but when it comes to small stuff the centre of the letter A, for example, goes missing.

 

EXAMPLE

Mach3 has a dozen or so fonts built into its engraving wizard and about half of these are open type and ideal for engraving purposes but it only supports the typesetting of one line of text at a time. This is not too much of a problem but it is fiddly and time consuming to calculate the X & Y start coordinates for each line separately.

A free software, StickFont by Scott Martinez is a single stroke text to G-Code converter and is extremely useful for small characters. Unfortunately it does not scale up well (as all characters are constructed from straight lines) and it becomes blocky and untidy for characters larger than say 10mm heights.

There is other software out there which does enable the setup of multi line text perfectly but so far I have not found a really good version to try before I buy. If you find one please let me know, my e-mail is on page one.

Using an impact engraver is extremely simple, a small bracket to fit the, usually hand held, device to the Z axis is all that is required. Results obtained are very much dependant on the material used, and I am still experimenting with various materials and I will post photos when available.

Lifting very heavy objects, with or without lifting tackle, is not without its dangers. It would be wise to have another person, if only as an observer, with you rather than to go it alone. Protective footwear is not a bad thing. Toes are precious too.

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This graduated scale 0 - 360 degrees has been made from engraving laminate (Traffolite) it is 74mm in diameter and has been engraved 0.4mm deep with a 30 degree engraving point. The centre hole and outside profile was cut with a 2mm diameter side and end router bit designed for glass fibre printed circuit board profiling.

It has been made to be used with my 4th Axis project as a visual indication of rotational position.

 

This pen holder was engraved, again with a 30 degree engraving point using the Mach3 typeface which is part of the engraving wizard.

Another interesting engraving method is to use a small, low powered diode laser which can be fitted directly to the Z axis and by setting the focus to the surface of the work and then disabling any subsequent Z moves a conventional engraving toolpath can be used (vector graphics).

The feed rate has to be set very low (around 20mm per minute) a faster feed rate produces a thin line and a slower feed rate a thicker line so some trial and error is required here to get it just right (it is essentially producing a scorch or burn mark on the surface of the work - pyro engraving).

Lasers, such as this, are not suitable for use on all materials - they tend to favour surfaces with low reflectivity or materials with a dark colour.

There are more details of this process and my setup on the Low Power Lasers page.

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Some more engraving examples.

A short video of an impact engraver in action, this one is a Burgess hand held tool for which I have made a clamp to secure it to the Z axis.

The material being engraved is hard anodized aluminium which causes excessive wear to conventional engraving points but impact tools just seem to love hard surfaces.

I have been using the Mach3 Impact / Laser Engraver plugin quite a lot recently with the laser and thought it was about time I tried it for Impact work.

 

This engraving was produced using an electro-magnet supplied by robotfactory.it

The magnet was driven with just one phase of a bipolar stepper motor driver, in full step mode and at a federate of 300mm/min it took just over 2 hours to complete the 95mm x 95mm image.

 

 

A typical Braille sign made by the well established process of drilling a pattern of holes, relating to the Braille characters, to a depth of just over half the diameter then inserting (interference fit) spherical balls (in this case 440 stainless). The online interpreter I used gave the Grade 2 contraction of replacing the ing with a single character but in this instance I stuck with Grade 1.

 

Something perhaps of interest, is that when using a ball insertion tool the same toolpath used for drilling the holes can be used, with offset, for inserting the balls - quite a time saver.

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