I’m writing this as an informational post that, if done correctly (which is highly unlikely), then it should show some differences in the Epilog and Universal machines. I encourage others to add to this review. I'm no expert and I'm new to lasers so I could very well have said something that is incorrect. My comparison would be between the Epilog Helix and the Universal PLS4.60. Both are 45W. Both have a travel range of 24” x 18”.
You can click on any photos for larger one's to appear so you can see the details better.
Weight :
Epilog Helix - 180lbs
Universal PLS4.60 - 270lbs
Motion system :
Helix - Uses servo motors, belt, pulley, and encoder strip. Carriage assembly rides on 2 Thompson shafts that are on the left and right of the machine. The shaft on the left hand side sits in fixed Delrin like material bushings. The right hand shaft sits in two Delrin like bushings that rest in slots, so the shaft can move, as it floats in the bracket. This design removes the need to align the shafts with each other. This design is also quite rigid at each end, but allows for deflection in the middle of the range, as the shaft is able to flex with no support other than at the 2 ends on the left hand side.
PLS4.60 - Uses high speed stepper motors, belt and pulley system. Carriage assembly rides on two rail systems affixed to the inside of the cabinet. The rails are lined up and locked in place. They are 1 ½” x 1 ¼” machined aluminum. The carriage rides on these rails via a series of Kevlar rollers which are spring loaded that pull against each other to keep the tension level high as to keep any vibration from entering the motion system. This system is very rigid and there is no play in the system.
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Cabinet :
Not a big difference in size from one machine to the other. The ULS is perhaps a few inches larger. The most noticeable difference is the solid glass lid on the ULS, which makes it Rohm compliant (some European standard that requires no lead to be used in the machine?). The lid is heavy and has 2 gas struts, one on each side, to assist in opening the lid. Both machines have a storage shelf under the body of the machine, built into the stand.
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Focus :
There is a substantial difference in the way the two machines deal with focusing the laser. In some respects, they can be identical. With both machines, for the laser to react properly, it needs to be set a certain distance from the object it’s burning.
On the Epilog, you have two choices, automatic and manual focus. On the head where the mirror rests, there is a small plunger. When you select Auto Focus and hit the start button, the machine will go to the first area of the burn and the table will rise (Z-Axis) until the work hits the plunger. When that hits, it backs itself down a predetermined amount and the machine, in theory, is in focus. It appears to work quite well. The second method is to use Manual Focus and set the distance yourself. There is a gauge that comes with the machine that’s held onto the mirror assembly with small magnets. You place the gauge on the machine and you press up/down buttons on the control panel until that gauge moves slightly. You are then in focus. Automatic focus is nice if you have one part, but if you have more than one of the same part to run, it can be a real pain. Once it’s focused, it’s no need to focus it every time you change your material. It takes 10 seconds or so to focus automatically, so if you want to run multiple sheets of material, then you’ll either have to send the job over twice, once with automatic and once with manual focus selected, it you’ll have to use manual focus and take the time to manually focus that first job, which takes about 60 seconds. If you change material thickness, you need to refocus the beam to that material thickness. If you do a large number of small quantity jobs, and they vary in thickness, you would have to focus each one of the jobs.
On the ULS, you can manually focus the machine as well. There is a gauge that goes against the mirror assembly and touches your work. Once it moves, you are all set. However, there is a substantial difference in the way the automatic side of it works. In the driver, one question it asks is "Material Thickness" (if you are using the materials database, or if not, then it shows up as a “Z-Axis” setting). You can type the thickness or click up/down arrows to enter the size. Once you do that, you’re all set. The machine knows where the Z-Axis is at all times, and it knows how far from the focal plane the table is. What that allows for is for you to change jobs with varying material thicknesses, and never having to refocus the machine to adjust for it. It does it automatically. There is also an “Automatic Focus” that uses sensors inside the cabinet that shoot light (or some signal) across the bed and it reads the top of the material.
Air Assist :
There are substantial differences in the two air assist systems.
Helix- The air assist on the Helix consists of an input on the back of the machine, which goes into a solenoid, then through a spiral formed tiny air hose that goes across the i-beam and into a small metal tube that is bent downwards to blow air on the area being burned. It requires a small, airbrush type compressor that usually costs $50 or less. You turn the air assist compressor on and it gently blows mild air out until the command for a vector cut is received. Once that signal comes in to the solenoid, it opens the airflow up to a max of 30psi (taken from the label on the back of the machine that says "30 PSI Max"). With the advanced color mapping, there are settings to control whether or not the air assist is used at all, in rastering, vectoring, or both.
PLS- You have two choices on air assist, non-computer controlled and computer controlled. We have the computer controlled variation, so I can only comment on that. It requires a larger volume of air than the Helix. I believe the manual suggests 3.0 CFM at 60PSI, which you won’t get from a hobby store airbrush compressor. There are several differences in this system. At the location of each mirror within the system, there are tiny filtered outlets. These are at all locations inside the operator section of the cabinet as well as under covers. When you turn on air assist, it blows tiny amount of air at each mirror location to prevent contaminates from settling on the mirrors. Around the mirror assembly where the lens is, there the air comes out in a wash, but also has a nose cone that you install. When you install the nose cone (one of the smallest set screws you’ll ever see), the air is directed right down on the cut. The beam actually travels through the middle of the cone. In the print driver, you select the color (black, red, etc.) and you associate different air settings for different colors. For instance, you may want 25 PSI for rastering, and then wide open for vectoring, or off completely. You set that in the driver and regulates the flow as it’s running. It’s a very sophisticated system. One thing you cannot do is run the machine with the air off and the nose cone on. It says that it will cause a vacuum and pull up debris into the lens area and prematurely damage the lens. A larger compressor to handle this can run some good money and can be quite loud if it’s in the same room. ULS offers a compressor for this, but it’s quite expensive, in the thousands of dollars. Also, the air must be particle free and dry air, meaning you’ll need some sort of filter and air drier.
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Print Driver
Helix - Comes with a print driver that has a variety of features. For most normal jobs, you’ll use the basics of the driver. You click the print button from your software package, then you select the "printer", which would be the Helix, and then you select the advanced tab, which brings up a variety of options. From there you have control over raster speed/power as well as vector speed/power. You select the power/speed setting by looking at a table provided in the user manual. It gives different settings for common materials depending on the DPI you output as. You can select the output to be 300,400,600, or 1200 DPI while rastering, and when Vector cutting, you select the frequency between 1-1000. Once you get the settings where you want them, you can save them for that material. The settings are for that particular thickness material only. If you manually tweak settings and change them, and don’t save them, they are gone forever.
PLS- The PLS system works a little differently. The driver is really integrated into a piece of job control software. You follow the same steps, you print from your software, click on the advanced tab, and you’ll be looking at a screen that has two tabs, one manual, one automatic. In the automatic mode, you have a selection of types of materials (Stone, Wood, Glass, Metal, etc.). You select the category and up comes a list of predefined materials. You select that material, enter the thickness, and you are done. You enter the material thickness for 2 reasons. One for the machine to focus, and two is so the machine can use the correct power. They have cut the materials, thick and thin, and entered those parameters. It uses those parameters to adjust the power/speed settings for the thickness you input. You can enter new categories or new materials as you wish and it’s a fairly complete method of doing it. It appears that once you have set a material up, it’s pretty much set for good, no matter what thickness of that material you use in the future. That’s the theory. I have not used it long enough to know how true this is.
If you select the manual mode, then you have control over a variety of things as well. The color mapping is done from here, mapping different powers/speed/air assist options. This next section is a little different from the Helix, as you have two settings for rastering, one is PPI and one is Image Density. The PPI controls the spacing between the dots it burns moving in the X-Axis. The Image Density controls the amount of dots in the Y-Axis. You can also select "Image Enhancement" which brings up 4 more fine tuning options. You can control "Density, Contrast, Definition and Tuning". There is a procedure for tuning each piece of material for maximum clarity of the image. It involves burning test patterns and text and then adjusting each of those 4 controls until the image is razor sharp. Once you set that, you can save it so you don’t have to do it again.
Once you agree to all and send the job to the printer, you are really sending it to a job control program. It keeps track of all the jobs ran, the times, settings, etc. You can specify the number of jobs to retain information for. Default is 2000. From here, you are looking at a graphic representation of the table and what’s in that job. You have a set of buttons that replicate the buttons on the machine. You can press them on the screen and it acts as if you pressed the button on the actual machine. You can start, pause, stop jobs in progress from your computer. There is an estimate feature where it will simulate running the job and give you a time. It appears to be fairly close in the jobs I have tested. Once you hit the "Go" button and the laser is burning, you’ll see the screen simulate what’s actually being cut on the machine, line by line. You can minimize that at any time or open it up and any time.
Rotary attachment :
Helix- The Epilog system is a unit that has two sets of dual rollers, one end fixed, one end moves back and forth and has a jack screw mechanism which allows you to raise and lower that end. It's basically aluminum discs with o-ring grooves cut in them and then o-rings installed. You just lay the item on the rollers, adjust the one end so the surface is level. When you turn off the machine and install the rotary attachment and turn it back on, it recognizes the rotary attachment and sets the y-axis zero to be on the centerline of the rotary unit. It's incredibly simple to use, but not extremely accurate in it's rotation. The item being engraved just floats on the rotating o-rings, so it can slip or move minute amounts which can cause some accuracy issues if you are doing precision rotary work. If you are just doing simple engraving on a bottle or glass, this shouldn't be an issue.
PLS- The Universal approach is very different. The unit is much beefier (if that's a technical term) and it consists of a set of centers. One side is mounted (where the motor is) and one side slides back and forth. Each side has an aluminum cone, one concave, one convex with rubber strips on the angled surfaces. You “sandwich” the item between the two cones and lock the tailstock down. It appears to be good for glasses and similar items, but doing things such as drumsticks or pens, or small round, solid objects is going to require some engineering on your part. You can remove the discs and make things to hold various items, but that all takes time. This item is no where near as easy or quick to use as the Epilog model. You really have to start to say “how am I going to hold this” when you have rotary projects for this. Also, the “headstock” and “tailstock” areas are quite tall, and doing something very small, such as a pen could run into some interference problems with the laser head hitting the headstock or tailstock. It might be okay, I haven't tried it, but just looking at it, it's going to be VERY tight and close and you'd have to be very careful not to crash the machine. Having said all of that, it's very accurate and geared towards a much higher level of precision. In the driver, there is a scaling factor that will allow you to make some very fine adjustments to the rotation to make it perfect.
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Vector Table :
Helix – The Helix comes with a honeycomb table that has a piece of stainless steel (magnetic stainless at that) on top of that, which has some small holes in it. The vector table looks to be about 1/2” to 5/8” thick. You don't want to push it, as it will bend and cause the material not to sit flat. There are two holes in the back of the bed where it pulls exhaust through. It does a reasonable job. To do non-vector cutting work, you pivot the guide rulers up and put the stainless sheet down, then close the rulers back down.
PLS – The PLS has a separate vector cutting table which has to be installed and removed each time. The vector table is a sheet metal box about 6 inches deep with a honeycomb top on it. Noticeably different is the thickness of the honeycomb table. It appears to be about 1” thick or maybe slightly more. Same type material as the Epilog (appears to be). The backside of the vector table has a piece of ducting that you can adjust. You set the table in the machine and then adjust the ductwork flush with the back of the machine. You lock that in and it's all set for good. What happens there is when it's cutting, the ductwork lines up with the opening in the back of the cabinet. It draws considerably more air through that system than the Epilog. Block off the top of the table that's outside of your work area and it's enough airflow to pull a vacuum and hold your thin work down. It is an expensive option, but if you cut through material, you don't have much choice. When you remove it, you are left with a solid aluminum table that's about 3/4” thick with rulers on the edges.
Laser Replacement and Alignment
Helix – There are a variety of reasons you will have to align the laser. One being, if you remove the laser from the cabinet. I'll talk about that process rather than what could be other reasons for having to align it. You must remove the back cover to expose access to the laser tube itself. You will need to remove several screws and unplug several connections to allow the tube to come out. Once the laser comes out, it will need to be realigned regardless if it's a replacement or the original. There are several steps to doing that alignment. You have to first line up the red dot pointer. There is a plastic cap with a target on it that goes in a spot on the side of the mirror assembly. You turn the red dot pointer on and see where it hits the target. You use a series of three screws to adjust the the pointer to the center of the target. You have to make sure it hits the center of the target in the 4 corners of the table. Once that's done, you cover the target with tape, send a job over and have it burn a mark on the tape in the top left corner. You note the relationship between the burn mark and the red dot pointer. There are 3 (I think ) sets of mirror adjustments that move the beam in various locations on the table. You follow a guide that tells you which mirror you adjust for each point on the table. You do this in 3 of the corners of the table, with the 4th corner being a byproduct of the adjustments of the other 3. Once those burn marks line up with the center mark on the target in all 4 corners, the laser is aligned. The tubes used are made by Coherent Laser.
PLS – The PLS has a cover on the back side of the machine that has two quick release devices that, when pressed, opens up and exposes the laser tube. You unhook the cables, lift the laser up and it comes off. No screws. To install it, you reverse that, and it's done. There is no need to align the laser. Doesn't matter if it's the same tube or a new one, or even a different wattage tube. The tubes are made by Universal Laser.
At the time of writing this, the cost to recharge the laser tube is considerably less expensive on the Universal versus the Epilog.
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I am sure I could have gone into a lot more detail, but my hopes were to put this up and allow others to offer up either more technical information or ask questions. It's not by any means meant to say one is better than the other, only to point out the differences in the two to help people make an educated buying decision. I firmly believe that both machines have markets and there is a lot of overlap in that market area. However, there are areas where they do not overlap and one clearly does something the other does not, or does the same task better, which might be something that a potential buyer needs. For example, there are some real differences in the rotary attachment that could easily be a deciding factor for someone looking to do a lot of small rotary work. Or there may be someone who requires a high degree of accuracy in their rotary work. One's not better than the other, they are just different.
It is highly likely that I have said something that is incorrect on both machines. If so, please note it and I'll edit the post to correct it. I hope this is helpful to someone who is considering purchasing a machine. You don't find much information comparing models, but rather just people saying they are pleased with their machines. Hopefully we can get some more people to offer up some comparisons between machines if they are in a position to do so.
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) without freaking out that my laser was broken after sitting for a week unused. I still have not spent nearly enough time as I would like to on it, but I have played enough that I feel comfortable giving my initial thoughts.
No further emails, no further calls... I don't know what happened, but I was already too close to make a decision to try and track down a sales rep. Trotec was out.
)
Originally Posted by Michael Simpson Virgina
