GLOWFORGE X AXIS RIBBON CABLE REPLACEMENT

The following information is provided for educational reference ONLY. All repairs should be undertaken by a qualified engineer. The use of the following information is done so entirely at your own risk! Kent Lasers is an INDEPENDENT service provider and not affiliated with any machine brand or manufacturer. **MAINS POWER SHOULD BE REMOVED BEFORE ATTEMPTING ANY REPAIR OR SERVICE**

The Glowforge laser cutting system was launched via a kick-starter campaign, to an eager-awaiting customer base. These systems promised, ease-of-use and a "professional" grade design. Unfortunately during our service visits to repair these machines we would consider the quality and durability of these systems to be of basic entry-level hobbyist grade, certainly not production quality. It would appear, from our findings, that these machines are built to a tight budget, utilising low-end hardware, and dubious design practises, these will be detailed below.

 

The common faults we have encountered, are lack of meaningful air assist, which leaves burn marks on surfaces, and dark sooty cut edges.

 

Various electrical faults including the notorious split ribbon cable(s).

 

Poor component design/layout consideration.

Overheating due to lack of tube cooling capacity (which limits the time jobs can be run)

Poor software functionality.

From inside the cutting area, we will locate the tool-head end of the ribbon cable, to remove it from the PCB, a small amount of downward pressure should be placed on the locking tab, and the cable gently removed towards the right-hand-side of the machine.

The cable, which is clearly damaged (the conductor traces have all snapped) can now be rotated and pulled out from under the tool-head PCB.

 

Please note that the tool-head can also be removed easily, as it it affixed to the gantry via neodymium magnets. We however preferred to leave this component in place to avoid further strain on the cable and connector. 

The cable can now be moved out from the underside of the PCB.

Moving to the centre of the gantry, underneath the black guide plate, the ribbon cable is affixed to the aluminium gantry structure via double-sided adhesive tape; the cable must be removed from this adhesive

Gently tease the cable from the adhesive, and pull free.

Moving further to the left-hand-side of the machine, the cable is traced through a plastic retaining clip. This is held in place via 8 locking tabs, which can easily be removed by placing gentle pressure towards the inside area of the clip.

Be careful not to place any pressure on  the ribbon cable, even though this part will be scrapped, it is good practise not to cause any further damage to removed parts.

Notice also how the cable is routed very close to the stepper motor, which drives the X axis. These motors have a tendency to get quite warm, thus require space to breathe. Adequate component separation is not only good design practise, but essential for long-term reliability (not the case unfortunately here).

Please also note that this machine is a low-hours unit, with less than 50 hours estimated cutting time. The amount of tar, cutting debris, and dust is indicative of poor fume extraction. The extractor fan is integrated into the machine, and is under-rated for this application. (Further images below).

At this point we have nearly half of the cable free'd. You can see the kinking and strain that the cable has endured.

We must now prepare the drag-chain; this step will make removal of the old cable easier.

Very gently insert a flat-blade screwdriver into the cable-carrier joint (we chose the 8th section from the gantry)

 

Extreme care must be taken not to allow the blade of the driver to enter the internal area of this carrier, as not to puncture cables.

 

Note this is a Chinese branded cable carrier, which do not offer long-service life. An IGUS branded carrier would have been a much better solution for a "pro" grade device, offering low friction surfaces and less wear on cables. 

It is now time to remove the left-hand-side panel from the machine "body".

There are two screws at the rear, located on an aluminium bracket, and a single screw in the front (underneath the rubber strip)

Be very careful when removing these, as they do not locate into threaded inserts, and simply "self tap" into plastic.

The rear-most screw is partially obscured by the lid hinges, thus a slight angle must be used when removing this fixing.

Retain the screws for re-use in a safe place!

Finally, for the removal of the side panel, we need to gain access to 4 spring-clips. Three of these are located along the internal side face of this moulding, with the fourth being at the rear of the machine, underneath the hinge assembly. 

We found it is easiest to place a small amount of pressure on the outer casing plastic through these round holes, and at the same time applying upwards pressure to the outside of (the top section) of the casing.

This can be slightly difficult; gentle persistence is key, the side panel is always removed in the upwards direction, no cables are attached to this part therefore do not worry about snagging wiring or components.

Once the side panel is removed, place it carefully to one side, remembering that this part contains a glass fascia, which can be easily damaged/smashed.

With the side panel removed, full access can be achieved to the control PCB located in the left-hand side of the cutter. Remove the controller side of the cable using the same method as the other end, taking care not to apply too much pressure. The cable can then be pulled through the carrier-chain using a small driver bit, or piece of rigid tube.

Note how filthy the electronics, heat-sink and general area of the machine is. This is due to all of the cutting fumes, debris and dirt being extracted over these components. This is extremely poor design, as accumulation of dirt and fumes will weaken plastic parts over time, reduce cooling efficiency, and damage sensitive components. Additionally with residues from cutting acrylics and plywood, this will eventually form a thick tar-like sludge (which is conductive). This is very likely to cause eventual electronics failure(s). 

With the old cable removed, we can see the extensive damage due to wear. In our opinion, this is unacceptable from a low-hours set, and indicative of poor design. The cable is extensively worn along its entire length. Additionally the area of cable exposed to the cutting area looks as though it has been hit from the laser beam, or reflection from cut materials. 

The new cable can now be installed by threading it through the drag chain; (THE PLASTIC TAB ON THE CONNECTOR SHOULD FACE UPWARDS).

This is a unfortunately another delicate process, as this type of cable is not designed to be kinked, excessively twisted, or folded beyond its bending radius.

A soft plastic insertion tool is used to push the cable incrementally through the cable carrier, under no circumstances should a metal tool be used for this process.

The tool-head end of the cable is then pulled gently through the end of the carrier, and fed underneath the laser tube output aperture.

The new cable is then fed through the opposing end of the cable carrier using the same method of push-feeding. The cable can now also be fed through the plastic retaining clip, and the clip re-installed. Note there is a 90-degree fold of the cable within this plastic clip, we suggest avoiding creasing the cable and leaving a small radius on the cable. The cable should exit this clip with the connector tab facing DOWN.

The screws which retain the control-end of the cable carrier will require removal to give enough flexibility to pull the remaining cable through, without damage. This can be achieved by gently separating the coolant and high-tension cable to one side. Extreme care must be taken here as the silicon outer-jacket of this type of cable/tubing can be damaged very easily.

 

Finally pull the cable through, removing all slack, and re-connect the cable to its mating connector on the control PCB.

 

We would like to draw reference here the the red high-tension cable. This cable carries around 26,000 volts at around 18mA in order to drive the laser tube. This type of cable (although made of flexible silicon) is not designated to be flexed or placed under strain once installed. The internal conductors are 8 strands of very fine tin-plated copper, which is VERY delicate. The proximity of the high-tension cable to the ribbon cable, which carries very small control signals is exceptionally poor design. Mains, and high voltage signals/supplies MUST ALWAYS BE SEPARATED BY A CONSIDERABLE MARGIN.

Potential failures here could cause catastrophic results, and any electrical "noise" passing from one conductor-to-another could cause glitches and controller/system crashes/stalls. (This is based on similar electromagnetic  principles to NFC, wireless charging and RF "contactless" payment devices)  to which we are all familiar.

Note the amount of dirt accumulation around these sensitive components.

With the cable threaded, and all connectors replaced the system can now be re-assembled. It is good practise to clean as much dirt from the system as possible using compressed air. The refitting of the side-panel is the exact reverse of removal.

With everything re-installed it is possible to manually move the tool-head to check for free-movement. From the above video, the rubbing of the cable can clearly be heard against the black protective plate. It may be possible to install a piece of soft low-friction material on the underside of this plate to increase the lifespan of this cable.

Our conclusion on these systems is that they do not meet the requirements for durability when using in a commercial sense. The design and mechanical engineering incorporated into these machines is ideal for a hobby product, that only endures infrequent use in thin-sheet, and other non-demanding materials. However if you intend to use these systems during the course of business, or will rely on it in any meaningful capacity we would recommend researching alternatives.

 

The software may be slick and have a clean visual interface, however there are now alternatives (such as LightBurn which offers MAC compatibility). Interface software which offers excellent functionality, advanced processing power and does not require a "live" internet connection is now fairly commonplace, even on entry-level equipment.

The ribbon cables do not appear to be the only source of potential wear on these systems. With lack of proper linear bearings, we have also noticed excessive play in the motion system. The image opposite demonstrating plastic residue on the guide-rails from excessive wear of the guide wheels, resulting in slack in the motion system, and thus poor quality cut parts. 

For a much better industrial-grade alternative see here!

Another area of concern is the ducting supplied with this system, which is made from very light-duty material.

You can see from these images the creases have caused numerous punctures in the duct, which will allow cutting fumes to vent into the working environment. (As evidenced by the complaints of smell from this user)

We would recommend utilising PU spiral wound ducting, which is designed for fume extraction applications.

To conclude these systems offer below-average performance and cut quality. After fully calibrating this machine there is still excessive burn on top surfaces of parts and charred edges. This is even when utilising Glowforge's "proof-grade" materials.

You can also see from scribe'd lines that there is no control of corner power, this results in excessive burning on corners of lines (where the tool-head has to de-accelerate into complex geometry) again, unacceptable on a system sold as a "professional" system.

© 2020 by Kent Lasers based in Maidstone, Kent | Quality UK laser cutters

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