techasist

What's the catch?!

No catch at all!
You give me a laser ready plan and i will laser cut it for you for FREE!
I get to use the plan for myself in return.

Why?!

I have been into helis for too long and I would like to give scratch building a plane/planes for a change.
I have a 100Watt C02 Laser cutting machine in the garage which is not seeing much use and I would like to donate something back to the forum, as I have been a long time reader, but I must say that I have not contributed much in terms of posts.

What's Required.

Laser Cut components can be achieved via either one or a combination of these options:

Supply CAD Files:
Providing me with CAD (Computer Aided Drawing) Files is the most cost-efficient and accurate method of getting exactly what you want. CAD files are not just scanned plans or drawings.

FILE FORMATS:

I can work directly with these files, but I am not limited to; I could probably convert from one format to another.
Your drawings must be at the scale that you want the model to be.
Save your completed files in any of the following formats:
.dxf .dwg .ai .eps .skb

Adobe Illustrator files:

GENERAL COMPONENT SPECIFICATIONS:
- All components drawn to the exact scale you wish your parts to be cut, preferably to 3 decimal place accuracy.
- All cut lines to be cut completely through to be the same colour (ie.Black).
- All scribe/text markings another colour (whatever colour as long as it is identified ie. “RED = 2mm engrave&rdquo.
- Areas you want engraved rather than cut please use a fill colour rather than just an outline and indicate the
approximate depth of engraving you desire.
- Set all line thicknesses to 0.25pt, the default minimum.
- Be sure all parts drawn are as a Compound Path – otherwise the Laser machine will cut your part as a series of
separate lines and curves which may result in stepping.
- Remove any duplicate lines to avoid ‘double cutting’ on the one line – which tends to widen the kerf and can burn
the material. Intersecting lines are fine however.
- Indicate the required material and the desired material thickness for every group of parts.
- For parts where you want multiple copies, you can either duplicate the part and ‘nest’ the required quantity together
or indicate clearly that you want multiples of a certain part.
- “Create Outlines” for all text to avoid issues with mismatching fonts. If you are using text to mark parts for
identification, where possible use a dedicated CAD font ie. TXT.shx, being a highly simplified hairline font it will help
to keep laser machine cut time to a minimum.

AutoCAD/TurboCAD files:

GENERAL COMPONENT SPECIFICATIONS:
- All components drawn to the exact scale you wish your parts to be cut, preferably to 3 decimal place accuracy.
- All cut lines to be cut completely through to be the same colour (ie.Black).
- All scribe/text markings another colour (whatever colour as long as it is identified ie. “RED = 2mm engrave&rdquo.
- Areas you want engraved rather than cut please use a fill colour rather than just an outline and indicate the
approximate depth of engraving you desire.
- Set all line thicknesses to 0mm or the program minimum.
- Every component is to be Joined Polylines; this reduces the need for the laser to stop and start at the connecting
points of every line and curve.
- No Splines to be left un-exploded since the laser machine will also cut the ‘invisible’ Spline handles - ugly results!
Explode or convert Splines to Polylines at a minimum of 80-100 segments per curve entity - otherwise the resultant
Polyline will have a coarse ‘stepped’ curve. 200 segments per curve entity is recommended for really smooth curves.
Think of this as ‘curve resolution’ - the higher the number of segments, the smoother the cut result will be. can, however,
smooth the curves on the machine itself, but some data might be lost in this process.
- Remove any duplicate lines to avoid ‘double cutting’ on the one line – which tends to widen the kerf and can burn
the material. Intersecting lines are fine however.
- Indicate the required material and the desired material thickness for every group of parts.
- For parts where you want multiple copies, you can either duplicate the part and ‘nest’ the required quantity together
or indicate clearly that you want multiples of a certain part.
- “Explode” or “Break Apart” all text into Polylines to avoid issues with mismatching fonts. If you are using text to mark
parts for identification, where possible use a dedicated CAD font ie. TXT.shx, being a highly simplified hairline font it
will help to keep laser machine cut time to a minimum, and my electricity bill also!

[img]file:///C:/Users/TECHAS~1/AppData/Local/Temp/moz-screenshot.png[/img]
OFFSET:

Where dimensional accuracy is important, adjustment can be made to compensate for the small amount of material
removed during cutting - an effect of any cutting process. This is an extremely small amount in laser cutting, and it is
consistent so therefore can easily be compensated for, giving accurate parts that fit like you intended. The laser head
centers the cut precisely on your digital line and with plywood/acrylic typically 0.1mm of material is removed either
side of the line. With balsawood and some soft plastics, typically 0.2mm of material is removed either side of the cut
line. Therefore to adjust and compensate for this (to create parts which will come out measuring the same as your
drawings), the outer edge of each component is to be ‘offset’ to enlarge for all exterior cutting, and offset inward to
reduce for internal cutouts. The following figures may be used when applying offset yourself:

0.1mm for Ply or Acrylic parts
0.2mm for Balsa parts

These offset values have been determined by a lot of testing and they will produce very nice interference fits for
parts designed to slot/puzzle/dovetail together.
For example, if you want a finished component to be 20mm wide, draw it as 20.2mm wide for ply/acrylic, and
20.4mm for balsa - the part will be ‘reduced’ in width in the cutting process and will finish up being 20mm wide.
If you want a hole in your Ply part to be cut to 20mm diameter, draw it as a circle of 19.8mm diameter - the cutout will
‘widen’ in the cutting process and will end up measuring 20mm.
If you wish leave it to us and we will apply kerf compensation to your files – just make all of your drawings
dimensionally accurate and we will make sure your parts are cut to your dimensions.

HOLD-IN TABS:
When parts are set up for laser cutting it is very important to add small gaps around the perimeter of all parts.
These gaps become tiny uncut sections which serve to hold the parts in the parent material sheet during and after
cutting, which is important for the following reasons:
- Parts are protected for shipping, greatly reducing damage from handling/shock during transit.
- Parts are protected from damage during the cutting process while other parts on the same sheet are being cut.
If the parts are allowed to drop out of the parent sheet they run the very real risk of being ‘run over’ by the
laser beam while it is cutting other parts. This leads to damaged parts and often breakage from the fall from
the parent sheet, which is elevated in the cutting jig.
- All parts are set out for easy identification and removal from the sheet.
- Most importantly, parts cannot partly drop from the sheet and protrude into the path of the moving laser head.
If snagged during operation, the laser head is driven by very powerful motors and will damage the entire sheet
being processed, with likely damage to the machine.
A number of methods for producing hold-in tabs exist, the preferred method being to ‘trim’ the perimeter using pre-set
double lines as a trim fence. These double lines (shown below in green) are set apart at the required distance
depending on the material being processed. The hold-in tab dimensions are as follows:
Hold-in tabs gaps should be: [0.3mm for Acrylic] [0.5mm for Plywood] [2.0mm for Balsawood]

Please see attached image (rib) for sample.

As per this sample component, tabs should be set at points around the perimeter at intervals no further than 150mm
apart. Set the tabs on easily accessible areas of the component to ease removal and cleaning up of the area.
Small cutouts whose longest dimension are less than 30mm [such as the light blue cutous shown above] may be left
un-tabbed to fall out of the component and discarded as scrap. If you wish to retain any small cutout areas add tabs
to them as per the outer perimeter.
*Note: all hold-in tab processing must be done AFTER offset has been applied to you parts. This is important
because if tabs are added before the parts are offset, the process of offsetting will reduce the tab gaps, rendering
them unable to support the components properly.

All parts you wish to have cut from plywood or acrylic can be nested to a rectangle 1150mm x 750mm, and all of this
area is useable. All Balsawood parts can be nested to a rectangle of
900mm x 85mm, again all of this area is useable.
Parts should be spaced at least 2-3mm apart for all plywood/acrylic cutting - this should be increased to 5-6mm for
parts to be cut from 5-6.5mm thick balsa. Be mindful of grain direction when rotating parts to nest together on the
sheet - in both ply and balsa the grain will run along the 1200mm length.

I am located in Melbourne, Australia. If you can supply me the materials, I will cut the parts and ship it back to you at your expense of course. Shipping is not very expensive, even to the U.S.

salat

My Feedback: (4)

Cool!!!

Prboz

I would like to know how you managed to get one in your garage and not have any work for it

I am in Geelong, Go the Cats (Hope your not a Saints supporter)

I am currently building an F4U but have made a CNC Router using a Dremel.

Would love to convert to Laser but by the look of it yours is a commerical unit.

Regards

Prboz

Yuu

Post more data on the CNC router, Please. I saw an article in Flying Models some time age that used a 'Roto-zip' and four stepper motors amd some home-made plywood framing. It looked like I could make one, but I've lost the article. Half my life is spent looking for things I had in my hand just a minute ago.....

techasist

Go CATS!!!

3W150Crazy

My Feedback: (-2)

i have a romain reaserch 101inch mig 3 laser ready for you to cut
would you like to??

techasist

Yes, no problem. Is the DXF laser ready?

Campgems

What is the width of your work area? Also by ready to cut, I assume that we will nest all parts of like thickness onto workable stock size sheets?

Are you able to handle imperal measurements, or do we need to convert to metric?

The offset is interesting, I would have thought that an offset should be built into the drawing or into the cut path. Of course, .2mm isn't much more than a swipe of sand paper to enlarge a cut out if needed.

Which version of DXFfiles do you like. I use Rhino 3d and it will export to several versions. Ialso have Ilistrator, but have never learned to use it.

Don

techasist

Hi Don,

I also have Rhino and you can send me rhino files if you want or any recent Autocad *.dxf* files.

Metric is best for me, thanks.

The work area is 1150mm x 750mm.

The offset will depend on the type and thickness of material to be cut. If I'm cutting 1mm thick MDF, the kerf is so small that the cut part actually stays on the sheet, for 6mm or 12mm MDF the kerf is more like .2mm or .3mm.

dolanosa

Mate,

Once I have finished the plans for the little F3A plane I'm making, I'll send you the DXF.  You then will have to be the lab rat to try it out.  It will be a 40 sized pattern plane.  Right now I'm trying to get help from other RCU members on the best way to build this.  Once a consensus comes in, the plan will be sent to you.  Cheers!


Butch

FlyerInOKC

My Feedback: (6)

How far behind in cutting are you?

cloudancer03

My Feedback: (22)

do you really cut kits for a nominal price???I have a hyperbipe set of plans and would love someone to cvut most of it ..

grover1

Has this guy done any cutting yet ?
Or is he just collecting plans .

PARCS46

My Feedback: (35)

Hey Grover: It seems to me that techasist is totaly sincere, but you presented a very reasonable question, which seems to have went unanswered? If I'm offering a free service, I would not let a serious question, such as yours go unanswered at all? Makes you wonder, doesn't it! PARCS46

grover1

PARCS46 Yes it doses makes you wonder.

I sent a bit of a plane to him and was going to send the hole plane on a CD to his home .
It is to big to send by email.

I emailed him two weeks ago to get his home address but no reply.

So that is why I ask the question

PARCS46

My Feedback: (35)

Hey Grover: Two weeks is a long time waiting for a response for your e mail? Depending on your set of values, whereby one would stand by his/her given word, I'd probably would get R/C Universe involved. Techasist may be making bogus statements! Now that in itself is no biggie, but when you post them in an open forum, one should be taked to task for such behavior! PARCS46

highfly3D

CHITO MAX......????

Puff The Magic Dragon

My Feedback: (2)

highfly3D I have to disagree about the Yak. The best is a Pitts S1S. Uncle Curtis's Gift to the world of aerobatics. Try an inverted snap with the Yak, then try it with a Pitts S1S. See which is more beautiful.

marymn

Hi..

thats nice to hear
go ahead!!!

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Marking Systems