A few general questions about engraving

[Eric Edgette]

First off, this website is great, you guys are very helpful and friendly to newcomers. I do have a few questions after reading though the forum.

I am considering a laser engraver with a work size of 24"x12" (possibly a mini 24) or 16"x12" (a zing or similar). Now I know most people so go as big as you can afford, so I'm still up in the air there, my main issue is power. Will a 25watt tube cut for what I need? I'm not sure yet. What is the limit to the depth of cutting for 25watts? or 35? Is there some type of chart out there? The main thing I read about is power going hand in hand with speed, I can understand that, just not sure about cutting though.

Also, can you use the cutting ability to complete jobs that a cnc router might normally do? Such as cutting a channel into a block of acrylic to make POP sign base?

I know corel is very popular with most engravers and I plan on buying it to work with before investing in a laser (I normally use photoshop or AI), but the one thing I'm not sure about is changing the depth of cuts within one design. It depends on the colors you have set in corel? I would want to be able to do things like shown at the top of this PDF that says 3D http://www.epilogfiles.com/brochures/epilog_brochure.pdf

Lastly, I looked at the thread here http://www.sawmillcreek.org/showthread.php?t=100885&highlight=paintball and I'm not sure what the guy is asking as far as his problem, especially this statement "keep the beam coherent for a longer distance"? If I did an item that had a varrying surface like this what would be the best way to go about it?

Thanks for the help guys.

Just for background information, I am looking to add this service to my existing business. I already do small run custom vinyls and some local sign work. I work from home and want something new to accompany what I already do. I've read through other startups and will not try to limit myself so one area of engraving.

[Scott Shepherd]

Hi Eric, Welcome to the Creek! I can't answer all of your questions, but I'll put my 2 cents worth in. Things like the 3D image you speak of look great for sample and demos, but they are a very hard item to market and sell, in my opinion. They take multiple passes and are slow.

You cannot cut a "slot" like a router.

One some machines, you can vary the power and speed by color. This allows for deeper burning in places, lighter in others, but you're talking small differences in depth. You can expect to go between .001" and .020" per pass. Just guessing on that, I haven't actually tested and measured it, but at max power, it's still not like a CNC router by any means.

The problem in that paintball post is that the beam is shaped like a hourglass. At the smallest point, where it comes together, is where it's meant to perform best. The further it gets away from the material, the wider the beam is, the less focused it is. So things that have different levels can be a challenge or you may not be able to do them in some cases. They make different focal length lens, and those focal lengths change the "sweet spot" on the beam (and change the diameter of the beam as well). A larger lens will give a larger sweet spot, but has a larger spot size. So larger lens can handle variations in the material thickness a little better. Smaller lens can't handle much variation at all.

Hope that helps some.

[Marc Myer]

Others will have much more to offer on this, but get as much power as you can. I have a Mini 18 35w and love it, but would welcome more power. The bed size is also important: I expected to not need a large bed, but my range of projects has expanded, and now I'd rather have a larger one as well. But hey, I love my engraver and have learned to use it creatively to over come the limitations I imposed on it!

Secondly, Adobe Illustrator is great to use with your laser as well, I have AI and Corel, but still use AI a bit more, as I'm so familiar with it. Corel's great, though, and most use it and love it.
But don't you hate trying to master new software, and memorize different ways to do the same thing?

[James Stokes]

For a sign shop you would be much better off with the cnc router than a laser, With the cnc you could cut thicker letters in many differant materials. With a 25 watt laser your limit would be about 1/4 inch acrylic.

[Eric Edgette]

James,I wouldn't say I'm a dedicated sign shop, far from it. I just happen to do some signs for locals and mostly sell small run custom vinyls mostly in the range of 2"-8" wide and from 1-50 in quantity. What can a 35w laser cut through, 1/2" acrylic? How about wood? Similar thicknesses to acrylic?

Scott, thanks for the explanation of the beam, that makes much better sense to me.

Marc, AI can output directly to your mini 18 as well? That's good to know, I would rather only use one program especially one I already have.

[Joe Pelonio]

Whether you must have Corel or can go directly from ai varies by laser make, as does thickness vs wattage. With my 45 watt I can cut most 3/8" materials
in one pass (wood and acrylic) but not 1/2".

As a sign shop I found the laser to be a valuable addition. The main advantage for a CNC would be cutting PVC letters and shapes, that I still have to send out, but in most cases have been able to convince them to use acrylic. Keep in mind that PVC produces toxic and corrosive gasses when burned, and invalidate a laser's warranty.The second advantage is size, most CNCs will allow for larger letter/logo sizes than most lasers. I have to send out any logo or letter with pieces larger than 12"x24".

For cutting a channel, a hand held router with a clamped on straightedge
will work for the pop displays. What I have done also is create the channel above the face of the base by gluing on 2 thin acrylic strips the right distance apart.

If people ask you for small acrylic letters, engraved name badges and desk name plates, as mine did, then a laser is a good choice. Also look at the competition. For me there was a lot of CNC and rotary engraving people around, but no lasers.

[Doug Griffith]

Marc, AI can output directly to your mini 18 as well? That's good to know, I would rather only use one program especially one I already have.

Just so you know, I'm one of the few here who outputs directly from AI. If great support is what you are looking for, such as that found here at SMC, outputting from Corel may be a better option. But then again, I poke my head in here daily so will keep my eyes open.

Cheers,
Doug

[Eric Edgette]

Thanks for the tips Joe. The things I considered getting a CNC router to do can be done with a laser. They include cutting small designs and shapes from acrylic or delrin that is 1/8" thick to 1/4" thick. I really don't think I need to go thicker, as these parts will be similar to other items being sold but will have my designs instead of the competition.

My local area is rather small, I know there are a few rotary engraving shops (one might have a laser). I'm not sure how much competition they will be for me because I am mostly going to gear my sales to go with my internet business and try to do tradeshows around the area. I still need to look into the tradeshow thing more to see if other laser users do what I want to do.

[Joe Pelonio]

I'm not sure how much competition they will be for me because I am mostly going to gear my sales to go with my internet business and try to do tradeshows around the area. I still need to look into the tradeshow thing more to see if other laser users do what I want to do.
By trade shows it sounds like you mean craft shows? When I considered doing them, I went to many in the local area to see what others were doing. Typically there were 2-3 laser shop people with booths, and 6-8 with hand made items, and most of those had signs reading something like "hand made, not laser". Of course, the laser items were less expensive.

If I were to do them I would stick to the smaller local farmer's market or "Saturday Market" type which have much lower exhibitor rates, and less competition. Last summer the manager of one local market here told me that people are holding onto their money more and that she wanted to attract people selling less expensive items that were more affordable.
I can't imaging what it might be like next summer.

[Larry Bratton]

Medium table size, as much power as you can afford. 25 watts will be pretty limited.

Knowing what I know now, after having owned a top end Epilog for nearly two years, if I had it to do over, I would invest my money in a good CNC router. I had a router before the laser and it's a nice compliment, but a CNC router with the proper software and some creativity, can be very profitable out of the box.

[Eric Edgette]

Can you explain what limits the 25watt will have? What can the larger power due (besides being faster and cutting through thicker items) that the 25 watt can't?

I plan to do mostly anodized aluminum, wood, acrylic, things like that. To me I don't see a reason for a cnc router or I would have purchased one already.

[Doug Griffith]

If you're planning to turn a profit from the laser, faster is better. More power will also open doors to materials and thicknesses you haven't even contemplated.

[Larry Bratton]

Eric,
If your going to be cutting thin material only and just doing engraving then the laser is fine. I am just saying that a CNC router can cut material and do things you simply can't do with a laser and vice versa. I suppose it depends on the market your going after.
For example, that anodized aluminum your speaking of,,try cutting that with a laser. Doesn't matter how thin it is, a 25 watt nor a 120 watt for that matter will cut it. I can also tell you that 1/4" acrylic cut with a 25watt machine would be very slow. I can only cut 1/4" with a 40watt at about 6% speed and it takes 100% power and high frequency.
Somehow, the word "laser" conjures up visions of lightning like speeds..not close to true for processing of material. On the other hand, I can take a piece of solid surface material (Corian) 1/2" thick and I can cut out an intricate design in a matter of seconds. 1/2" Corian is impossible for 40 watt Epilog.

[Eric Edgette]

I understand. I'm still waiting on the brochures from several companies to see the pricing, that way I can tell how much power I can afford.

The few parts I want to cut will be thin, small and not very intricate. At least the parts I plan on cutting.

Here is another question for you guys, why is it that I see some engraved anodized aluminum and you can still tell what color the anodizing was, beneath the laser? For example, on some red parts the engraving looks pinkish and sometimes on black there is a noticeable gray? Is that a fault in the engravers settings?

[Rodne Gold]

I can tell you that for general signage a CnC is the way to go and not a laser. However as doug says , a laser will allow you to initially make more money cos of it's versatility and the ability to do extremely fine work as well as opening up new markets.
We have both and the combo of the laser and CnC is synergistic and the results are way more than the sum of the 2.
Lasering anodised is really leaching out the dyes that the anodiser dips em in to give em colour..sometimes the laser cannot leach these dyes 100% , depending on the dye and the sealing of the anodising and you get a residual colour..very little you can do to get it completely white other than blasting it with power and trying to vaporise the anodisin , which is not the point of lasering anodised. The whole point of lasering it is NOT to remove the anodised layer

[Eric Edgette]

Ok, I didn't know that about not going through the anodizing. Would that be a trial and error thing you'd need to work on with aluminum to make sure you didn't go to deep?

I'm really getting excited about doing laser work, I'm waiting on the brochures for pricing (hopefully it'll be what I am expecting) before I go any further but everything you can do is just so neat.

[Michael Hunter]

Assuming that you end up with a "big name" laser (not chinese), the user manual should give you approximate settings to get you going on all sorts of different materials, including anodised aluminium.

For each material you will then need to do tests to make sure that the settings are right for you. There are lots of variables including the actual power of the laser tube in your machine (which shouldn't be less than the manufacturer states, but if you are lucky could be quite a bit more). Also the generic setting will let you make a mark/cut, but you might find the results are more pleasing with a bit more or less power.

For lasering anodised aluminium, I use two different settings according to the job -
The first is quite a high power which I use for very fine detail work (e.g. text less than 1mm high). At this power a "normal" job is spoilt because the anodised layer is blasted away.
The second setting is for "normal" work - text up to 24pt and "ordinary" graphics/logos.
Occasionally the second setting is still too powerful if there are large areas of engraving, so I have to tone it down a bit more for some jobs.

Similarly with wood - I have settings stored for several different woods and also for various effects on a particular wood.

Even the laserable sign plastics need slightly different settings, according to the colour of the top layer.

From the above you will see that although the machine will work straight out of the box, there is a significant learning curve to ascend before you can be confident of achieving quality work every time. Don't let this put you off though - it is part of the fun!

[Eric Edgette]

I definitely plan on long nights with many used practices pieces. I have already found a place that sells thing anodized aluminum sheets so I can try that out and a few others that have wood for a fair price.

I'm still waiting on my brochures for more information and pricing. I'm going to go american and have been leaning towards a new Epilog but have considered the money savings going used. I like the warranty and everything you get with buying new.

Hopefully someone will read this and answer, but I was wondering with engraved plastic if you could 3d cut designs into it? I've read tutorials for wood, but didn't see plastic. I'm also wondering if I were to cut away designs into the substrate (maybe 1/16 depth) if I could bring the polished look back by using a flame? I know this is commonplace when cutting lexan or plexiglass, just not sure if it would get rid of the engraving marks or look.

[Frank Corker]

.......Hopefully someone will read this and answer, but I was wondering with engraved plastic if you could 3d cut designs into it? I've read tutorials for wood, but didn't see plastic. I'm also wondering if I were to cut away designs into the substrate (maybe 1/16 depth) if I could bring the polished look back by using a flame? I know this is commonplace when cutting lexan or plexiglass, just not sure if it would get rid of the engraving marks or look.

I routed the edges of acrylic and used flame polishing to remove the cut marks (http://www.sawmillcreek.org/showthread.php?t=75258&page=2) and as can be seen from the above post and the picture below, a very good result. As for removing marks from 'plastic' - this obviously depends on your plastic.

[Rodne Gold]

There is almost no strategy to remove the engraving marks made by the laser into plastics barring a "polishing" pass - for example if you deep engraved , then do a pass over those sections with less power than you used to engrave , around 1/4 of the power ..this serves in some way to "remelt" the plastics giving a smoother effect.
A flame is going to affect areas which were unenegraved - so use the laser to do the "flame polishing"

[Scott Shepherd]

You are going to have a very difficult time making money from 3D work in anything you do with the laser. It's very slow at giving depth and you'll be making multiple passes to get any depth to it.

Keep in mind, something 10" x 10" in 3D could take as long as 40 minutes to run one pass. Now make that into 3 or 4 passes to get the depth and you're looking at a price point that starts way up there. I can't find retail consumers willing to pay that price for things they want. The average person isn't going to cough up $250 for a 10" x 10" piece.

While most manufacturers offer 3D and they use it to sell you at the demo, be really aware that it's very time consuming, which will translate into a very high cost item, which might be way out of your target market's price range.

[Eric Edgette]

Thanks for the sample pics and tips guys. The size of the parts I was thinking of making would be about 1.5" x 3.5". After designing and doing some samples I'll have to figure out if customers would pay the premium for them.

[Scott Shepherd]

Thanks for the sample pics and tips guys. The size of the parts I was thinking of making would be about 1.5" x 3.5". After designing and doing some samples I'll have to figure out if customers would pay the premium for them.

Do that upfront and make them demo your files. Then you'll have real life examples of what it takes BEFORE you buy the machine.

[Eric Edgette]

I think I finally decided on a 35 watt mini 18. The price is right where I thought it would be and there is a special for this month with an additional 1 year on the warranty for free. One of the traveling guys from the closest distributor is coming my way on Wednesday to do a demo and show me more about the machine. That really couldn't have worked out better and saves me a 3.5 hour drive.

Thanks for all of the help and sample pictures.

Frank, I'm having trouble using corel to give me the gradiant for 3d cutting. I did the walk though on the epilog site and converted some shapes fine when doing the gradiant all the way to the center, however I only want the edges done. I tried to use the other options instead of fading to the center but I get a bunch of solid lines instead of a gradiant. I think it's because I set the inside to no fill instead of 50% black so I don't get a gradiant, but I don't want the inside to be engraved, just the edges. How can I fix that?

[Mark Winlund]

Regarding anodized aluminum...the grey background is because of the anodizing process, not the amount of power used while engraving. To demonstrate this, laser a piece of plain coated colored aluminum, and the engraving will come out with a mirror finish. We do some plaques this way when the customer wants "mirror finish letters". The same is true for coated brass stock. The only difference between "laser brass" and the brass that we have been using for years is that the brass underneath the color coat has been polished.

The point of using anodized aluminum is it's durability and outdoor weatherability.

To get these materials, Main Trophy Supply is one of the more reliable sources.

Mark

[Rodne Gold]

There is a market for semi 3d engraved products , and that is making masters for guys that do resin and metal spin casting. One has to be intelligent when doing these masters in that engraved surfaces are "rough" and so that has to be incorporated as a "feature" , one can get smooth planes by cutting masters out out thin substrates and building them up or just micro polishing (using dremels and the like) and by using materials that do not ridge sunstantially when engraved to depth.
One of the problems you often encounter is the piece moves somewhat , either the machines inherent vibration or the piece itseld expands cos of the heat - thus it has to be extrmely stably held to get best results. Another problem is remelt or dust from lasering covering unegraved surfaces leading to variable engraving. True 3dis not a good option , most lasers have at least 8 to 16 colours that can be assigned power and speed and you can utilise these to give a multidepth engraving rather than continuously variable contours ... this is also a lot more controlable. Most materials you use will have to withstand at least 120c heating if moulds are vulcanised , perspex will work and give a true cavity but wont last vulcanisation. Chemical woods and resins and phenolics work well.
The idea is to do multiple masters for these guys , the normal process would be to have a single master and then cast many copies of this and use those castings to fill a mould cavity - problem is that definition has dropped and shrinkage occurs in a 2nd gen casting and the full production would be a 3rd gen casting if you use 2nd gen to fill moulds - leading to even more shrinkage and ill defined surfaces. One of the problems you face doing masters is "vertical" cuts , IE the wall of a recess would be vertical, leading to problems when mould rubber is released or the spun cast item is released from the high ttemp silicon moulds - stamp mode on most lasers solve this as it gives a "shoulder" , IE the walls of a recess would slope inward to the bottom , you dont get
_|||____|||_ , you get _/|\_____/|\_