My engraving nose

[Wendy]

Hello CNC friends and cockpitbuilders,

Because engraving always took to much time, you have to do it letter per letter and adjust the Z-axis until the letter is nicely engraved. Because of this nightmare that is caused by panel irregularities, I decided to design a special nose.

And now finally my engraving nose is ready and I can show it to you. I've designed it myself but because I do not have a lathe I had a metal workshop made the complete engraving unit.


The principle is very simple, turning the copper wheel lets you move a metal canister up and down and by doing this the engraving depth can be set to a few hundred mm. The small black screw can block the setting. The Z-axis is floating free on the panel with a constant pressure of 350 gram and the white plastic nose follows the irregularities in the panel. All this ensures a constant engraving depth all over the panel.


The first tests completed according to plan. What a luxury, whole lines of text at once, and engraving was right from the first time. The plastic on the nose does not scratch the panel.
The weight of the current floating Z-axis on the panel is approximately 350 grams. The excess weight of the Kress was taken off with two feathers.


I've included a panel which formerly had a faulty engraving. Watch all text that is upright (newly engraved with the nose), so it's a bit of a mess but you may well see the difference between the old engraving (upside down) and the new engraving. This panel was a good test because the surface had large differences (greater than 0.2 mm).

Enjoy, Wendy

http://www.querit.eu/FS/Engraving/Nose_Foto_1.jpg

http://www.querit.eu/FS/Engraving/Nose_Foto_2.jpg

http://www.querit.eu/FS/Engraving/Nose_Foto_3.jpg

http://www.querit.eu/FS/Engraving/Nose_Test.jpg

[deering]

Wendy,

that's an interesting solution. Do you have a quick method of re-engaging the ball-screw for pocketing/profiling?

Jim.

[Wendy]

Hey Jim,

On the side of the Z-axis I can attach a small square part of aluminum and then the floating Z-axis becomes fixed again. Just a matter of 2 screws.

The engraving unit is attached to the router mounting plate with 2 screws and can also be removed easy.


Regards, Wendy

[deering]

Good stuff, Wendy.

Thanks, I'll have to think about something like that for my set-up.

Jim.

[riche543]

Wow thats fantastic wendy. I do find it hard to wrap my head around stuff like this , but my question is that you say the z-axis is floating free so how does the z-azis motor pickup the z to take it to the next letter ? would it be posiible to see a short video of this working as i think i will understand the way it is operating then.
Thankyou wendy.

[Wendy]

Hi Riche,

I don't have a video camera, so I'm not able to show you.

You can compare it with having a big play on the Z-Axis up and down. So when I enable the floating mechanism the Z-axis can float around 15 mm. but is still driven by the ball-screw so that it can lift the router and go to the next letter. When he is at the next position (letter) then he goes lower then necessary so that floating is possible.

Regards, Wendy

[mondo50m]

Awesome job, Wendy. I know what you mean by having to do one letter at a time. Is it possible to get a drawing of the parts? This is one part htat is needed by everyone who owns a 'hobby' CNC router.

Milt

[Wendy]

Hey Milt,

I do not have a drawing of this. Just made a raw draft on paper and explained to the shop what I needed. I also left the mounting plate and router in the workshop to make it easy for them to make the part. I can provide you with some measurements if you like, let me know if you want them.

Regards, Wendy

[mondo50m]

That would be awesome, Wendy. I do not have the setup that you do, but I would like to take a stab at this.

Milt

[Jan737]

Hi Wendy,

Great job!!!!

Do you have a picture of the floating part with the 2 feathers?

Best regards

Jan Geurtsen

[Wendy]

hey Jan,

Here it is. This is actually an idea of Hessel.

Regards, Wendy

http://www.querit.eu/FS/Engraving/Nose_Feathers.jpg

[mondo50m]

What do you mean by feathers? The springs?

Milt

[Wendy]

Hi Milt,

Yes of course springs. I don't now why I wrote feathers (that has something to do with birds).


Regards, Wendy

[Jan737]

Hi Wendy

Thanks for the pictures.
I've seen the one of Hessel a few months ago.
I'm building a nose by my self, but due lack of time I'm not finished yet.

Best regards

Jan Geurtsen

[Joe Lavery]

Hi Wendy,

Brilliant piece of work as usual, beautifully made as well.
I'm in the process of choosing a CNC machine, which one do you use? did you find it a steep learning curve?

Regards
Joe.

[Wendy]

Hi Joe,

My machine is a Colinbus. It's a Belgian manufacturer. I'm happy with it after I changed a few smaller things. If you buy one make sure the structure is very solid, that is absolutely necessary together with a quality router.

The learning curve was not that easy, but if you have a problem we can help.

Regards, Wendy

[Joe Lavery]

Hi Wendy,
Thanks for that, I've been looking at the Zenbot 24" x 16" machine from America, it has a good write up and no real complaints to it's accuracy.
They advised me to use the Bosch GKF 600 Palm Router Kit with it, this is the stock tool holder they supply. Have you heard of this machine?

I see there are no prices on the Colinbus website, if you don't mind me asking what do they cost?

Regards
Joe.

[Hessel Oosten]

Here is the initial thread I made on the Dutch Elektor forum.
Although in Dutch, the pictures are clear I think.

The construction is cheaper ( only a few euro's) because I used as simple gas pipe.
This was possible because I use (for engraving) a small motor (Proxxon IB/E) with a collet of only 20 mm (i.c.t. the euro collet of the Kress: 43 mm).

http://www.elektor.nl/forum/forum/actuele-projecten/profiler/home-brew-engraving-head.1315632.lynkx

In this thread there is also a movie where the springs can be seen at work.

http://www.elektor.nl/StreamFile.lynkx?path=Uploads/Forum/Posts/P1120701.MOV

Hessel

[Wendy]

Hey Joe,

Here is a link to the order page of the "Profiler", that is the machine I have. I see that it is cheaper then what I have paid for it.
http://www.elektor.com/extra/profiler-milling-machine-from-a-kit.91274.lynkx
You will have to add a good router and mounting because the router that comes with the package is very bad quality.

Regards, Wendy

[Joe Lavery]

Hi Wendy,

Thanks for that but I think I'm going to go for the Zenbot, only because it has a larger work surface. Once it arrives I'll probably bombard you with questions.. (if you don't mind of course) ;).

Regards
Joe.

[Wendy]

Hi Joe,

Feel free to ask any question.


Regards, Wendy

[riche543]

Hi wendy

Just wanted too ask how the nose is going, I havnt got around too building one yet. but planing on building a hole new cnc machine so will incorporate a Engraving nose. Have you made any changes or adjustment to your design, Over at cnczone , one guy seems too think that the nose can scratch your work, I know you said yours dosent, have you found this at all. I asked over at cnczone for more ideas as , im not sure how too attach the nose as i will have 2 kress routers one cutting & one for engraving.
any thoughts would be great. cheers wendy.

Riche.

[Wendy]

Hello Riche,

Well he's doing fine (the nose), and he is not scratching the paint. One thing I would change is a smaller pitch for adjusting the depth.
Good luck witch building yours.

Regards, Wendy

[jonesthesoftware]

Hi Folks
I've just added an Autocad file in the downloads/micellaneous section, for my own design to make your own floating collet for engraving/PCB's. It has a 7mm shaft and fits in a collet adding about 65mm to your Z height( or lowering to more accurate). Uses ER11 collets. Set your engraving depth by the amount of tip protruding through the PTFE nose. I've had this made and it works fine BUT NOTE the PTFE nose must be as smooth as possible and a perfect hemisphere to minimise contact. The sliding fit between the part A and the oilite bush should be as close tolerance as possible.
regards
geoff

[riche543]

Hi wendy
Its me again.. I still havnt got round to building my nose yet but getting closer, i would like to ask you if you have any more pics or could explain the floating part of the z axis a little more. cant work it out from the pic on page 2 . Im very thick sometimes :???: when it comes to trying to work out how something works but once shown a few times i understand . was the same at school. I get the adjustable nose for depth but trying to decide/workout how to make the z float without making the whole z axis to bulky if you get me. (thought of v groove bearings & track) sorry to bring this back up again but from what ive seen on the net yours seems to the perfect nose for the job. Geoff thanks for posting that file too did D/load but couldnt work that one out either :oops:

Cheers
Richard.

[Wendy]

Hello Richard,

I'm afraid I don't have other pictures. There is nothing more to see. Normally the Z-axis is coupled fixed without any play. When you do engraving, the nose has to follow the material and that is why the Z-axis has to be able to move freely up and down for let's say 5 mm. When the first letter is engraved the router has to go to the next letter and the Z goes up with 10 mm taking the engraving nose 5 mm above the material. For the next letter the nose follows again the material within the play of 5 mm. The springs are there to help release the pressure of the Z-axis on the material. The Z-axis is heavy and weights more than 1,5 kg. so the springs keep the nose on the material with a pressure of only 300-400 grams.

Difficult to explain, but I hope you understand. Otherwise please ask.

Kind regards, Wendy

[Hessel Oosten]

Hi Richard,

I have the same mill as Wendy, Colinbus Profiler, to operate an engraving nose.

It can be VERY confusing that nearly NO-body can do it as we did, because we have the fluttering mechamism built in INTO our (so special) Z axis.
Never seen this in other mills, so you have to make a nose with INCLUDED fluttering mechanism.
A general mechanism is here:
http://www.colinbus.com/en/freehowto_en.htm
I have probably some info for you and a movie to show, but too big for upload here.
If you wish, write me a private message with your emailadress.

Hessel

[npbosch]

Thats beautiful made Wendy,

I made also a floating Z axis, from an old piece of aluminium that I adjusted a bit.
The only disadvantage is that I have to take of some parts of the z axis when I change milling - engraving. But it takes about 5 minutes far less than the tedious engraving of engraving one character at a time.

[riche543]

Thanks for reply Wendy & hessel, yes the confusing part for me is the linear/fluttering action without any play when it floats. I would like that info & movie hessel would be fantastic. Will pm you. Like the link you posted hessel , I would like too keep the floating part compact nice & compact, thanks again everyone for your help on this
Cheers
Rich

[riche543]

Thanks so much for all that info Hessel , very much appreciated
undertstanding it better now , Im thinking this one (see pic) will work for me.
My only question is , where marked in red are there some type of bearing or bush in there or just a very snugg fit as this part
must not have any play other wise it would affect the engraving right?
I have posted a few pics of the new cnc build here http://www.mycockpit.org/forums/showthread.php/24042-My-2nd-Build?p=128046#post128046
Thanks
Riche.


6132

[jonesthesoftware]

HI Guys
I'm following this thread with interest because engraving on my CNC is a pain because of the variations in paint thickness, material thickess and finding a good flat surface to work off. However I can't quite see the logic of suspending your spindle motor and all that metalwork and moving it further away from the ballscrew (which is the basis of accuracy in all CNC machines), and introducing more potential areas of lateral movement i.e bushes and bearings. This still leaves the basic principle of a presumably ball shaped tip actually resting on the material. Surely you should be looking to minimise the hardware involved which is why I've gone for a simple spring loaded collet extension. The principle is the same( ball end on material but there is only 1 point at which any play can be introduced and that is the point where one part slides into the other. What advantages does your designs have over my simplified version? What materials are you guys using as the "ball end" that sits on the material? I am not criticising your designs in any way but looking to improve my own engraving. I've had 2 floating collets made so far(at £120 each) and frankly the quality of the lathe work was rubbish the sliding fit wasn't close enough in tolerance and the smoothness of the Teflon ball tip wasn't good enough it left scratches on my paint.
kind regards
geoff

[Hessel Oosten]

My only question is , where marked in red are there some type of bearing or bush in there or just a very snugg fit as this part Must not have any play other wise it would affect the engraving right?

Rich,

Don't know, since this a a pic of a commercial one that I have never seen in reality.
BUT, the ONLY difficult (alias important) part of making this yourself, is the need of very tight fit in X and Y direction, BUT the very elegant/smooth going .. in Z direction of the sliding parts.

Glad you are now on your way !

Hessel

[Hessel Oosten]

Hi Geoff,

1. I think everyone agrees with you that all should be as tight as possible near the center of the main/first z axis. The fluttering "thing" a kind of second z axis ..

2. May be the differences of several of these things with your spring loaded .. collet is that that "thing" gives pressure on the surfce with risk of scratching ?

3. In the majority of other designs a mechanism is build in to reduce (!) the pressure on the material. In Wendy and my machine by pulling-springs (reducing the weight of the whole z axis and motor) and in the other desings (see pic in previous message) by a pressure-spring, nevertheless giving also pressure / weight reduction.

I can send you (if you wish) the same bunch of info I did send to Rich ?
Could be that it is overkill with all your technical knowledge.

My nose is teflon, smooth and soft, with some carvings to blow the dust from it (for scratching in pcb/copper and for not lifting the nose by dust in other cases).

Hessel

[riche543]

Going too order some of these. http://item.mobileweb.ebay.com.au/viewitem?itemId=300553706107. 4mm bushes will see how the tolorance is with them, it's harder to find the 4mm rod to go with them,might work for that design of the float. if anyone knows where too get the right rods for these please let me know
Cheers
Rich.

[jonesthesoftware]

Hi Hessel
I can see that the "weight reduction " by springs will work just fine, it's just I had reservations about the distancing of the cutting tip from the axis of movement and any play in the slides. Even 1 or 2 thousands of an inch of movement at the bushes/slides translates into several or even tens of thousandths at the cutter tip which is enough to ruin engraving.
I'm afraid I was unlucky in not being able to find a good quality engineering shop on 2 occasions to make my floating collet and I'm very reluctant to pay a third time.
Thanks for the offer of the info though but I won't be building that type of floating head in the forseeable future. I'm managing to get good engraving results at the moment by careful choice of materials and a good flat board to place materials on. I also have a "clock gauge" which I run over the material first to check flatness then put packing underneath for best results.
kind regards
geoff

[Hessel Oosten]

I also have a "clock gauge" which I run over the material first to check flatness then put packing underneath for best results.

And the best securuty without nose is of course to engrave only 2-4 letters at the same time.
I try 0.05 mm amd look, add 0.05 mm and look again. In most cases than, it's done.
In between these I rub the engraved channel with my finger, so rubbing the burrs into the engraved channel. The second pass they will be removed and the channel is again clear and the burrs are gone.

h.

[riche543]

Hi All

Well finally got round to finishing new cnc & got the engraving Head & nose done, its been a long time coming but glad i didnt cut corners , test results are great & no more too deep or completely miss opposite end because material or table isnt pefectly flat :D.
Also im using Compressed air to clear chips so thought i might as well use it for keeping the nose clean while engraving too, (Hole too the left of the white nose)
Also posted few more pics of cnc in my albums.
Thanks for the great replys too all my questions regarding this. Heres a few pics
Cheers
Riche.
:p

67626763676467656766

[Hessel Oosten]

Riche !

Looks GOOD +++, and a solid construction too !
The font type does not seems to be "aviation related", so we want to see it (mainly) in Futura MdBt in next messages ....:-).,

Hessel

[riche543]

Thanks Hessel
So pleased its finished & working well.
Talking of fonts ive been trying too hunt down Futura Md BT in a single line font or one that is virtually the same as Futura Md BT but single line? Reason i say this is wouldnt it engrave quicker if the toolpaths for engraving were single line , ?
Cheers
Riche.

[Hessel Oosten]

Hi Riche,

Sorry for late response; did not see the forum for some weeks.
Single line fonts are expensive and difficult to find.
I never found usable ones for us.

BUT, double lines are only a few seconds slower...

Use the internal spiral pattern, e.g. with a 0,3 or 0,2 mm mill.
In our lettering, which is so small, there is nearly place for a up and a down pass of the cutter. In that case the space is already filled. In e.g an "R" or a "B" at the narrow places there is only space for one pass.

Hope this helps,

Hessel

[riche543]

Thanks Hessel, yep had no luck finding anything with single line , Amazing that no one has converted more fonts for single line , anyway will have to experiment with tool settings etc. Thanks again
Cheers
Riche.

[jonesthesoftware]

Hi Richie
I don't know what software you are using for engraving, but I use Autocad to design everything and then import that .dwg file into Artcad for engraving and generally generating the cnc files. When I import the text from .dwg into Artcad it ends up with single line text which can then be engraved by using the "follow a vector" tool. You can also draw single lines to make your own text and cut using the same tool. Of course you will not then have "aircraft" style fonts as Hessel says. What is wrong with your text engraving? Too wide fonts? Are you cutting too deep with the wrong tool? Wrong tool specified in you cnc software?

regards
geoff

[Hessel Oosten]

Hi Rich, Geoff,

To menstion another possible option:

In an older toolpath generator I used (RAMS3D) I imported a double line dxf from AutoCAd.
In RAMS3D I choose a (fictive) mill diamter which was just about 49 % of the width of the double lines. Generated a toolpath which, of course, is than a single line just in the mid.
That line could be exported as a normal toolpath but also as ... a *new* dxf. That *new* dxf can be used for generating a single line toolpath. How complicated can you go ....-).
The double lines are no problem for me.
Geoff, I searched for the artcad you mentioned on Google but found nothing waht resembled a graphical program. Did I understand it well that when using that program no aircraft like-fonts (e.g. Futura MdBt etc.) are possible ?

Hessel

[jonesthesoftware]

Hi Hessel
the programme is ArtCAM see here
http://www.artcam.com/

Yes it has the full range of fonts, whatever windows fonts you have on your computer. I just mentioned the peculiarity of the programme that when it imports from Autocad, text comes across as single lines which I then have to delete and substitute with Futura Ltcn Bt(this is the narrowest of the Futura fonts).
I think engraving for backlighting must be the most difficult and frustrating task so far in cockpit building.
I've encountered so many problems in engraving with a cnc machine, table flatness, material flatness (acrylic is only within 0.1mm and paint is about 50 micron), blunt tools, paint not properly dried so not a crisp edge, speed of engraving, blowing, clearing/cooling of tip to prevent paint melting and sticking to tip etc, etc. I think I've just about got it all sorted. Only problem I haven't cracked is white text when the backlight is not on. I use opal acrylic, painted and engraved through, but it's a sort of grey text without the lights. I tried spraying white then brown and tried to engrave only through the brown but you need flatness of better than 50 microns or thereabouts. Can't get that without dedicating my cnc to engraving only. Of course I use it for everything else including making furniture, so I use sacrificial mdf sheets on the base table which again aren't flat.
AH the joys of cockpit building!

regards
geoff

[riche543]

Hi Geoff / hessel

I'm using vectric vcarve , I did find using futura LT came out ok , but still doing outline, It's a shame we couldn't get futura md bt one stroke straight out of windows fonts as it seems like lots of messing round just for text engraving.
Vcarve has a couple of single line fonts built in one being a futura font, but few letters don't come out very good

Riche

[riche543]

Looking on the net there seems too be some font design software out there , is it possible too use these to make one stroke futura md bt font for windows?
Don't think I'm smart enough too do this , just asking if it's possible?

Riche.

[jonesthesoftware]

Hi Riche
are you using the correct font because Futura Ltcn Bt is a narrower font than futura md bt?
regards
geoff

[Perik]

Hello

I have a short video showing 0,4mm Single Flute Endmill inside contour engraving session over here:

http://www.youtube.com/watch?feature=player_detailpage&list=UL2Ps87U2nOEE&v=2Ps87U2nOEE

I've tried different approaches but this is for me the best. An alternative for the brittle 0,4mm endmill,
you can try to use for instance a 15 degrees V-cutter with a flat tip of 0,2-0,3mm.
The clue is to take one "word" or small section at a time and lowering the tool step by step until
you take out just the paint.
Remember - this is not mass production ( I hope :-) ) and the time used for engraving is just a blink
of an eye compared to the overall spent time.

Concerning material I find that white PMMA (casted) or Hesaglas - for instance:
http://www.peerless-coatings.co.uk/acrylic.html give the best result.
I believe Hessel use ~1mm Hesaglas glued on top of transparent acrylic.
I use 6mm PMMA pocket milled from the back to get the appropriate thickness.

Anyway this is just my experience and without a huge investment in
a Laser “Turbo GT Plus”, I feel this is about as close as we can come
with a “mechanical” approach.

Happy millling

[jonesthesoftware]

Hi Per-Erik
thanks for that. I've just watched your youtube videos. Beautiful work, you have even more patience than I. Yes I am going to try both the hesaglas approach and 6mm white PMMA milled from the back. I already mill from the back but I used Opal acrylic because I didn't realise that the white had any transparency at all.
I use the 30deg V cutters and can get good results down to 3mm high text. Haven't tried any smaller yet. Because I was still learning the cnc and broke quite a lot of cutters in the process I bought chinese 30 deg V bits because they are cheap, but it took a while for me to realise that they were part of the problem. When I really looked at the tips some were broken and some of the edges weren't sharp. Changing to a better quality cutter made a world of difference.
ah well live and learn!
kind regards
geoff

[riche543]

Hi Geoff / per-erik
Geoff for me the futura md bt comes out too thick , even using 0.2mm 40 deg bit , maybe it's vcarve software making them too wide.?
Vcarve has option for fill or outline , fill would give me slightly narrower but takes such a long time just for one letter. I will take some pics of how they come out.
Per-Erik great video , what font are you using for that engraving?
The engraving nose I built for mine was proberly the best thing I've done, because I don't have too worry if material is not within 0.2 flatness, will always engrave same depth.
If your cnc can cut aluminum , you should think about making one ,
Cheers
Riche

[jonesthesoftware]

Hi Riche
just another thought, if you use the Futura Ltcn Bt font then in your cnc software setup , configure your cutter as wider than it actually is , the software will make an even narrower cut, obviously if the width of cutter tip is less than the minimum width of the font.

regards
geoff

[Perik]

Riche,

The font is Futura Md BT, 3,3mm height. Not sure if 100% correct size but it match the real quite well.
And yes I know I should have made a Floating Head though I feel the engraving is OK for now.
More important is that I need to make some progress on the Cockpit build ;-)
So that’s on the top of list right now and I'm at great speed for the moment fighting with Korry Guards.

Geoff,
I know I’m too much into time-consuming details but when you know it’s the guy behind
the “yoke” who's mostly the limiting factor, I can’t let that happen without at least try…
It’s like “sh** in - sh** out” ;-)

>80% of time is into making drawings (3D) which I fancy very much and I know the CNC
is doing mostly as told ;-)
The rest is a steep learning curve in tooling / methods / materials / paint / pcb / mechanics etc.
and I learn new stuff every day – that’s one of the good things about this approach.

About using Endmill versus V-cutter - my experience is that Endmill is easier to use
due the clean vertical cutting of the paint. Using V-cutter you need to have a lot more
control of depth / tip angle / tip width etc. and for sure you have to compensate somewhere if not
single stroke font is good enough.

[shearder]

Hi

What are you using as an engraving bit? Thanks in advance. i.e. degrees and tip size?

[Perik]

Hello,

Well, lately I’ve been using V-cutter (0,3mm flat tip / 10 degrees) like this one:
10XCARBIDE PCB Engraving Bit CNC Router Tool 10° 0 3mm | eBay (http://www.ebay.com/itm/10xCarbide-PCB-Engraving-Bit-CNC-Router-Tool-10-0-3mm-/140442982129?pt=LH_DefaultDomain_0&hash=item20b30dd6f1)
Performance is about the same as end-mill, but A LOT stronger.
I was feed up by those tiny end-mills accidently snapping off – not by milling but handling ;-)

[shearder]

Hey Perik

I have a set of 5 - 30* 0.1mm tip carbide engravers. AND i THINK i still have a set - somewhere - with a 10*, 20* and 30* engravers - can't remember tip size. OH and a 90* 0.5mm tip.

What end mill were you engraving with?

Hello,

Well, lately I’ve been using V-cutter (0,3mm flat tip / 10 degrees) like this one:
10XCARBIDE PCB Engraving Bit CNC Router Tool 10° 0 3mm | eBay (http://www.ebay.com/itm/10xCarbide-PCB-Engraving-Bit-CNC-Router-Tool-10-0-3mm-/140442982129?pt=LH_DefaultDomain_0&hash=item20b30dd6f1)
Performance is about the same as end-mill, but A LOT stronger.
I was feed up by those tiny end-mills accidently snapping off – not by milling but handling ;-)

[Perik]

Hello

I've used single flute 0,4mm mostly - 0,3mm can be hard to find as single flute and
is too thin and snaps just by looking at it. Dual flute is stronger but you'll experience more clogging.

Most of the letters we use do have space for 0,4mm when running inside
contour / pocket milling but some letters / segments of letters are too narrow.
Isolate those few letters in concern and apply this dirty trick - Tell your 2D
layout/path/gcode program that your bit is 0,38 mm or as small as necessary
to get the path generated. In real your bit is 0,4mm.
You will hardly notice the difference.

Another way is to do a quick edit of the letter in your 2D program (i.e. AutoCad)
and space out the specific line segments.

I've not experienced any "normal" letters/signs having trouble with 0,3mm end-mill/V-cutter.