Tuesday, March 5, 2019

The Voccell DLS Laser Cutter

The Voccell DLS 50 Laser Cutter
In December 2016, after 14 months of delays I canceled my Glowforge order and ordered a Voccell DLS 50W laser cutter. I received my DLS 5 months later in May 2017. The Voccell DLS 50 was $3500 at the time including the water chiller and shipping. Today Voccell lists the price at $5000.

Voccell is a Delaware company. The Voccell DLS is basically a custom version of the Storm laser cutter manufactured by G.Weike in China. The DLS was imported by Voccell and shipped from their warehouse in Arkansas. The DLS was delivered in a large wooden crate by a freight shipping company.
The crate
The Voccell DLS included a high quality S&A CW-5000 water chiller, a generic ventilation fan, a generic air compressor and all the hoses and cords necessary to hook it up. The package also included a fire extinguisher, tinted laser glasses, replacement lenses and cutting height gauges.

Setup
Setup was fairly straightforward. The documentation is clear and well organized.

The DLS laser cutter itself is a large steel box which weighs 150 lbs. You are not going to casually move this machine around. I found a 36 inch deep by 48 inch wide half-height metro cart with wheels to serve as a workbench. The chiller, the compressor and my air filtration system go on the lower shelf and the DLS laser cutter is on the top shelf at counter-height.
The Voccell DLS on the rolling metro cart at left. The S&A Chiller is on the shelf below.

The first step of setup required hooking up two rubber hoses and a control cable to the chiller and setting up the system to run distilled water from the chiller system to cool the glass CO2 laser tube. It is important to carefully follow the instructions to avoid forming air bubbles in the hoses or inside the laser tube. The S&A CW-5000 uses active refrigeration to chill the water it pumps through the laser system. The inclusion of a high quality chiller with the DLS allows the laser cutter to operate uninterrupted at high ambient air temperatures (Voccell claims up to 90-degrees F) and should extend the life of the glass CO2 laser.

The second step, the air compressor has to be connected to the DLS to provide air assist. Air assist blows a stream of air over the cut to evacuate smoke and debris away from the laser beam and to help keep smoke from staining your workpiece.

A 4" dryer hose connects to the side of the DLS and goes to an exhaust filtration system or to the supplied ventilation fan and then via another dryer hose out a window or vent. As with all laser cutters, the exhaust contains toxic laser-generated air contaminants (LGAC). It is vital that this exhaust be filtered or routed away from anywhere humans or animals will be breathing. (My articles here and here detail how I designed and built a suitable air filtration system -- the Fume Coffin.)

Fume Coffin Exhaust Filtration System (left)
Improved Pre-Filter for Fume Coffin
The DLS, the chiller, the ventilation fan (or the Fume Coffin filter system in my installation) and the air compressor are all hooked up to 120V AC. The ventilation fan and air compressor are on a single switched outlet strip since they only need to operate while the machine is cutting or engraving.

The DLS has a 16 inch by 24 inch (400mm x 600mm) cutting area. Materials can be 4.5" high. The DLS uses a manual crank to adjust the height of the cutting bed and adjust focus. The DLS came with both a knife edge slatted material tray and a honeycomb material tray. The honeycomb tray has fine gaps and can support smaller pieces. The honeycomb tray accepts magnets which can help hold material in place.

The DLS connects to your computer via a supplied USB cable. But the computer is only needed to transfer your cut projects to the DLS.

Operation
The system comes with a Windows program called VLaser which is a customized version of the ubiquitous control software for Chinese-made CO2 laser cutters using RuiDa control hardware. (Similar software goes by the names Laserworks, RDWorks, and LaserCut.)

An excellent third-party program called LightBurn allows the Voccell DLS to work equally well with a Macintosh, Windows or Linux computer. LightBurn costs $80 for the version compatible with the DLS's RuiDa controller. Generally, I've found that LightBurn does a better job with file imports than VLaser. I highly recommend LightBurn.

You import vector and raster files into VLaser or LightBurn to provide cutting and engraving definitions. From there you layout your cuts and engraving patterns in a virtual work area and set the appropriate laser speed and power parameters for each cut or engraving. The exact parameters for a cut or engraving will depend on the material, its thickness and the desired objective. A catalog of standard parameters for common materials is supplied by Voccell, but some experimentation will yield the best results with a specific material.

Once you have completed your layout you send the project to the DLS via USB cable. The control panel on the DLS is then used to set the far-right corner "origin" and check the "frame" or outer perimeter of the cut project and make sure it falls entirely within your blank material. The DLS has a visible red laser to see exactly where the invisible cutting laser beam will hit your material. Satisfied with the alignment of the layout on your material, you must make sure the air assist compressor and exhaust system and fan are turned on, then press "start" on the DLS to execute the cutting process.
The Visible Red Laser

Height of the lens is adjusted by raising or lowering the cutting bed with a manual crank. There is a 4.5" range. Gauges are provided to position the lens for optimal focus with standard materials. But I use a table of values and a cheap digital micrometer to get easily reproducible results.

Construction
My Voccell DLS came with a nominal 50W CO2 laser tube. Voccell also sells the DLS with a 70W laser tube.

Russ Sadler publishes the excellent Sarbar Multimedia YouTube channel where he examines the fine details of the design, operation and tuning of Chinese CO2 laser cutters. As part of the series he developed a simple device called the DoHICky and a system for testing the actual power output of a laser.

In May 2017 when the DLS was brand new I tested actual power output with a DoHICky. At 80% it was 43W, and at 100% power it was 46W. It is apparently typical that nominal power specifications ("50W") are higher than actual power output (46W). Actual power at the cut will also be affected by factors like mirror and lens alignment and efficiency. Also of note is that actual power plateaus between 41W and 46W above 70%.

I re-tested the DLS with the DoHICky in March 2019. After 20 months 80% power dropped 7W to 36W, and 100% power dropped 5W to 41W. So the DLS has lost 10% to 16% of its cutting power over 20 months. Again lens and mirror efficiency and alignment may play a role in the results.

It is expected that a glass CO2 laser tube's power will deteriorate over time no matter how much it is used, but some treatment like overdriving the tube and inadequate cooling can shorten a tube's life. So testing a CO2 laser over time can determine where a laser tube falls within its life cycle.
The bottom line is that glass CO2 laser tubes are consumables. You should expect that your laser cutter will need its CO2 laser tube replaced after a few years. Voccell currently charges $300 for a replacement. Suitable replacement laser tubes may be available from other sellers, but mileage may vary unless you know exactly what you are getting.

The chassis housing of the DLS is made of steel and is very solid and well engineered.

The actual CO2 laser is a 1000mm long glass tube housed at the back behind a hinged access panel with an 8" steel extension to cover the length of the tube. It is not necessary to access the tube except for service and to make sure the water cooling system hasn't got any air bubbles during setup.

The laser beam is reflected off a series of three mirrors to a lens on a two dimensional gantry where the cutting head focuses the laser beam onto the target material for cutting and engraving. Because the CO2 laser operates in the invisible infrared spectrum (10.6 micron wavelength), there is also a visible red laser that is coincident with the CO2 laser beam. The red laser allows you to easily aim the cutting beam and position your target material.
The cutting head in action.
The door panel to the cutting bed has a plastic window that allows you to easily observe progress. The plastic is opaque to the CO2 laser wavelength so there is no danger from laser exposure, but the laser cut is often very bright so the tinted glasses are a good idea when observing the cut. There is a magnetic interlock switch on the door panel that prevents the laser from running when the door is open.

There is no counterweight or pneumatic shock on the hefty door. So I rigged up a counterweight with a bottle of water on a cord to hold the door open.
Water bottle on pulley counterweight holds door open

The front of the DLS housing has another hinged panel that opens down to easily allow long material to be placed into the cutting bed. But the gantry system that guides the laser will still present obstacles to some material configurations.

The left side can also be opened with a key and a panel at the back of the housing can be unscrewed to facilitate even more configurations for oversized materials. So the DLS can be operated with 3 of the 4 sides open.

When operated with any of these panels open the DLS is a Class 4 laser. OSHA and other jurisdictions require strict laser safety protocols to be in place when operating a Class 4 laser. It is unlikely but possible that the CO2 laser beam might bounce off some reflective surface and get directed out of an opening when operating the laser cutter with side shielding removed. The laser beam loses power very quickly at any distance beyond the 2 inch focal length. But the unfocused beam still presents a serious eye injury hazard. Everyone in the room is required to wear wrap-around eye protection. (Direct exposure to the CO2 laser beam can cause instant eye damage or blindness, but clear plastic eye goggles are sufficient to block the laser beam.)

Voccell DLS 50W Components (partial list):
  • G.Weike Storm-style housing.
  • Yongli laser tube - 1000mm length.
  • RuiDa ST908(EC) controller board (similar to the RDLC220).
  • ZODA 85C17 ammeter.
  • WK60S power supply.
  • Filtemc FT127-10 single phase power filter.
  • Lens - fl = 2", aperture = 20mm.
  • JF-Motor 150FLJ3 300W 3300 rpm exhaust fan
  • Electrical Magnetic Air Pump ACO-012 air assist compressor
  • S&A CW-5000 chiller
Cutting and Performance 
The DLS generally does well with plywood up to ¼ inch. But plywoods vary in their internal composition. The laser handles different woods, glues and layers differently. It is often necessary to experiment on different materials to find the best and most consistent cutting parameters. The resulting char on the cut will vary, but can be minimized by optimizing the cut speed parameters and air assist. I find most scorch or smoke stain cleans easily with isopropyl alcohol. And char can be cleaned with alcohol and light sanding.

The DLS cuts through acrylic plexiglass very easily and precisely, but it is smelly. The CO2 laser actually vaporizes the acrylic resulting in a very clean cauterized edge.

Service and Maintenance
Voccell seems to be a minimal company, and their Delaware office is maybe just a proxy location. The DLS included a 12 month warranty. Many buyers have complained on Reddit that Voccell is very slow to respond. I have no experience with their service beyond a few email exchanges. The idea of shipping the 150 pound VLS laser back to their warehouse for service seems ridiculous.

When it comes time to replace the CO2 laser or service the machine hopefully Voccell will be able to help. Fortunately, the DLS uses fairly generic parts. Many of these parts are available on eBay or Alibaba. I suspect I can perform many maintenance operations or repairs myself. The DLS manual includes instructions for laser alignment, lens replacement and laser tube replacement.

I have now had the DLS for 20 months, and I have not had to perform any service or special maintenance. We will just have to see how that holds up going forward.

Voccell DLS 50 Laser Cutter Pros:
  • The DLS is a reliable and flexible design in a "50W" laser cutter.
  • Setup is straightforward but a bit involved. Typical for a laser cutter like this.
  • The documentation is thorough, well-written and clear. 
  • The DLS is easy to use with a straightforward control panel, manual height adjustment, red visible laser for material alignment and a USB computer connection. There are no gimmicky features like camera-controlled material alignment or autofocus. 
  • The DLS can be controlled with LightBurn from a Mac, Windows or Linux PC.
  • The DLS can accept a wide range of file formats including DXF through LightBurn or VLaser.
  • The included chiller allows the DLS to be operated safely in the summer in a non-air-conditioned garage or workshop. The chiller extends the life of the laser tube.
  • The DLS has a fairly generous 400mm by 600mm (16" by 24") cutting area. (80% more area than the Glowforge.) 
  • The DLS has flexible access to the cutting bed to allow large items to be cut or engraved.

Voccell DLS 50 Laser Cutter Cons:
  • Voccell is a minimal company that is sometimes unresponsive to customer service.
  • DLS 50 is at its core a G.Weike Storm with some additional quality control, upgraded parts and a warranty backed by US-based importer. The Storm can be purchased direct from China at a fraction of the cost of the Voccell DLS. But mileage may vary.
  • The included VLaser PC software can be somewhat fussy and idiosyncratic to use to control the DLS. Fortunately, there is lots of documentation available on the Internet on how to use the almost identical LaserCut, RDWorks, and Laserworks programs. Alternatively, the DLS can be run with the excellent LightBurn software. 
  • The door should have a counterweight or pneumatic shock to hold it open.
  • The DLS is large, heavy and not at all portable. 
  • The system's 45W laser limits the speed of cuts (thus cleanliness of the cut edge) and thickness of materials than can be cut. 
  • The DLS can handle materials only up to 4.5" deep. (Voccell reportedly sells an option for rotary engraving on glassware.)
Voccell DLS