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Author: Subject: Laser cutting with Pololu.com
bulerias1981
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[*] posted on 9-16-2011 at 12:43 PM
Laser cutting with Pololu.com


Hello,

Has anyone here dealt with Pololu.com to cut rosettes? I want to share a recent experience with an order of 3x Nahat style rosettes.

In this thread fast forward provided a pdf for this famous rosette by Abdo Nahat http://www.mikeouds.com/messageboard/viewthread.php?tid=11043#pid75...



I used this file and sent it to Pololu.com and left instructions in the comments field.

"This is a rosette for an Arabic oud. perhaps you've made some from others already. I need this rosette to be a diameter of 116mm, WITH an extra "outer" diameter of 130mm. (This surface is used to glue the piece to the bottom side of the instrument. Text) my name is John. Thanks."

I received the order a week or so later. And noticed two obvious issues with the order. 1) The black areas on the pdf I send out were NOT cut out. Just engraved. And 2) the inner circle isn't much of a circle because it has straight line defects occurring along its diameter. See here


So I wrote an e-mail explaining the issue. Attached photos. Here is what I wrote:

"To whom this may concern.

I received my order today, but there is a problem.

These are supposed to be rosettes, for musical instruments known as ouds. They cover the main hole on top of the instrument, which is like a guitar. They are made from various materials but the old Syrian ouds used bone or ivory. Now plastic can be used to make a beautiful rosette. Please see "rosette of god" attachment. That happens to be the same pattern I gave you to cut out with the laser.

If you see the photo, you'll notice that the rosette was engraved, and not CUT OUT. If you see the second file "DSCN2240_edit" you'll see that none of the holes were cut out. Also, there seems to have been a defect on the inner edges, where some of them came out with straight lines and not round.

So my question is, can your laser cut out the pattern fully? And if so, can I send these back to you? And if not, can I get a refund if your machines cant do it. If they can, I need this asap for an important customer (I'm a maker)

I appreciate your time, I'm sorry for the confusion, I understand mistakes happen. I hope you can help me with this."

I never received a phone call. So I phoned them. I received a woman, and told her the story. She opened her e-mail. And about 2 mins decided that this was my fault. The reason? I approved of the following file during my purchase.


It states that the "black line will be cut" and in parenthesis it says '130mm circle' then continues that the 116mm surface will be raster engraved (surface etched). Now when I read this, I assumed they meant black lines in the file I sent them will be "cut out" and "etched" away. The key word Pololu says that hold me responsible for are "engraved" So you can see, its a vague technicality.

When I mentioned that I'm not exactly asking for my money back, and would try another pattern, the girl (during the course of the conversation with a very condescending and sarcastic tone) told me at best they can give me partial credit! And that their machine cannot cut the pattern out due to its intricacy. When I told them they should reconsider giving me full credit, because I was considering having many rosettes cut by them, and if they will not humor me as a customer, I would be reluctant to order from them again. She coldly replies "well we spent the time to cut the material, and payed for shipping and credit card costs". For one, I payed the shipping! Two, I payed via paypal. And three, what point does she prove there?

So, they never called me to begin with as I requested when I sent my file. They never called me after I wrote them an e-mail, I had to call them. And they won't honor me a refund, NOR full credit if I send the non rosette-like rosettes back to them. I asked to speak with someone higher up. She replied, "I'm pretty much the one that makes the decisions". To me, this is like a murdered investigating his own crime. I tried a few times to persuade her from changing her mind, that she would be making a business mistake to make me eat the cost of this. She had no problem with her phone based two minute conclusion, and held strong to it.

I guess I have very fancy coffee table coasters (if only I had a coffee table!) I'm now $46 in the hole. Whenever I do business with my customers, if they're not happy with it, I replace it or offer full refund. If there is a communication issue, and the work wasn't correct, I also eat the costs in order to cater to the customer and keep them. These people do not seem to operate on the same principle.

What do you guys think?

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Jameel
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[*] posted on 9-16-2011 at 05:27 PM


John,

It's unfortunate that you had to eat the $46. On the other hand, you've learned a valuable lesson: be extremely specific when you commission someone to do work for you.

I've commissioned a fair amount of laser engraving in various materials (wood, micarta, bone, ivory) and there are tons of variables to consider. Material density, how it reacts to the laser, strength of the laser, material thickness, engraving time (how fast the laser moves, and how many times over the same area) and other variables. "Raster engraved" is exactly what was done to your blank. It's a common term used for laser engraving. Based on your very brief description and the contract, I'd say they delivered the goods as ordered. And they aren't hanging you out to dry by saying they can't "re-cut" the rosette. It would be nearly impossible to reposition the blank with the next pass cutting in exactly the same spot as the first pass. Your pattern would be pretty-much obliterated.

Next time you need to specify exactly what you need done, in clear language. People in this business like to get specific orders. It makes their life (and your's) much more pleasant. Better yet, find someone local with a laser engraver (you can probably find a list at the Epilog website) that you can visit in person. That will save tons of wasted time and frustration. Many people with these machines are passionate crafts people and hobbyists and would probably enjoy working with you on the cutting the shams.

If you want to reproduce this rosette you should go in with a program like Corel Draw or Adobe Illustrator and make the pattern crisp and clean. You'll also need to keep in mind that no area can have 360 degree cutouts, otherwise pieces will simply fall away. It's really easy to miss on these complex patterns with hundreds of cutouts. Believe me, I've done it before! The better drawing you start with, the better the shamsi will turn out.

Also keep in mind that lasers don't do well with cutting through extremely fine detail. Those areas will be extremely fragile and may get entirely cut away. Also keep in mind that just because a laser engraver can cut with little violence to the material (unlike a fret saw which stresses the material) that doesn't mean the material will be strong enough to keep its integrity after the pattern is cut. The Nahats backed up their bone and ivory shamsi with wood not for both strength while cutting, but also for strength after the cutting was done. When you cut away material leaving only very narrow sections, they need to be thick to hold up. I always back up my rosettes with walnut plywood. It's extremely strong and pretty much disappears behind the bone or ivory.

As for laser engraving in general, I suppose it depends on how good you want this to look. In my opinion, laser cut rosettes always look amateurish and factory-made. I would rather see a finely cut, simple pattern than a lousy complex one. As an aside, I think there are perhaps just a handful of people on the planet who are capable of cutting out this maqamat shamsa in bone or ivory to the level of Hamza's. And you would need bone of ivory to take this level of detail. I think even the best laser-engraved shamsi based on this pattern will end up looking like a mish-mash of shapes at best. Just my opinion. I'm not a fan of laser engraving unless you can do it so it looks completely NOT laser engraved. I haven't seen it yet.

I hope this info helps you John. Sorry about inserting my perhaps strong opinion on laser engraving. I have a rather eccentric opinion on being faithful to the quality of the best Nahats (must be my German side!)

Cheers!







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bulerias1981
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[*] posted on 9-16-2011 at 09:08 PM


Jameel, didn't realize you were half German!

The issue I had with the company I contracted to make rosettes has a few variables. As you can see the inner edge has straight lines for almost 65% of the inner part. They were supposed to call me, but didn't. To make a long story short, the main problem was communication. But they don't want to honor the customer in any way. So for that, they will surely lose my business for life. I'd never do business that way with any of my customers. I like to keep a good relationship with them at all costs. But maybe I'm just crazy?

About laser cut shamsas.. I also believe in doing bone shamsas by hand. However, its a time consuming process and not everyone has the money for this. So I'd like to offer laser cut alternatives to people. I'd like to have both options offered. I definitely agree that hand cut bone shamsa is much more beautiful, no question.
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Alfaraby
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[*] posted on 9-17-2011 at 01:32 AM


Jamil is absolutely right. It's just as time consuming as making a hand-made rosettes. I've been through this like Jamil has said & spent tens of hours in the laser shop till we got the final satisfying version of the rose I needed. the result was way beyond what Jamil called "amateurish and factory-made". The laser-cut roses I have cut look just "impossible", no burn traces & no fragile ends. It's the Illustrator or the Corel Draw that makes the job. The machine just carries out what you first design &/or plan. It has no mind, discretion or judgement. What you put is what you get.
As a sample, see the attached Nahat style Rose of poplar wood & other hard woods fingerboard I made for our great luthier Kamil Mowais from Nazareth, assembled on my 6/6/2011 new oud !

Cheers
Yours indeed
Alfaraby


kamil rose.jpg - 139kB Puzzle for grown-ups.jpg - 60kB Kamil Fingerboard.jpg - 78kB Kamil 06.06.2011.jpg - 182kB
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bulerias1981
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[*] posted on 9-17-2011 at 09:36 AM


beautiful oud, Alfaraby. How does it sound?
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Alfaraby
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[*] posted on 9-17-2011 at 01:47 PM


Quote: Originally posted by bulerias1981  
How does it sound?

Here it is on his second day !
Attachment: Kamil 2011 Second Day.mp3 (908kB)
This file has been downloaded 370 times
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bulerias1981
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[*] posted on 9-17-2011 at 01:57 PM


Aiawaaa. Mabrouk, 3oud kteer helou. Who is playing? Good oud player.
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Marina
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[*] posted on 9-17-2011 at 11:09 PM


Kamils ouds are great,
I performe on his oud all the time - phoo from Andalusian Orchestra + Kamil oud:

http://www.facebook.com/marinatosh#!/photo.php?fbid=237990046216203...

:cool:
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Faladel
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[*] posted on 9-18-2011 at 02:06 AM


Hello all

Jameel says this:

If you want to reproduce this rosette you should go in with a program like Corel Draw or Adobe Illustrator and make the pattern crisp and clean.


Someone can put the Pattern of this Shamsie drawn by Corel Draw in his real size????, because I have a craftsman who cuts to hand orders as difficult as this Shamsie, but he needs the staff to be able to work.
Thanks




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David.B
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[*] posted on 9-18-2011 at 02:47 AM


So this drawing turned into a moving rosette on the oud is about the fantasy! In addition it should be set upside down to read it in a mirror ;)

More seriously, the rosette is beautiful and I understand those who want a reproduction.

Theoretic Circle.jpg - 456kB
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