Ultimately, at the end of the day, the owner of any object coming off a vehicle/trailer/caravan will be subject to criminal charges for not ensuring the objects were secured correctly if causes injury or death to a person.

I had a friend who was lucky that he had a dashcam. He had a set of pipes come off from a vehicle in front of him. The driver tried to deflect it wasn’t his fault. The dashcam proved otherwise. He was sued for damages to my friend’s car.

Angle between the insert’s side-cutting edge and the line perpendicular to the milling cutter’s axis of rotation. Approach angle, which is also known as cutting edge angle, is used with metric units of measurement. See lead angle.

Distance between the bottom of the cut and the uncut surface of the workpiece, measured in a direction at right angles to the machined surface of the workpiece.

“That said, the milling method requires significantly less horsepower than drilling from solid,” he said, “so the milling solution is often used when the customer is restricted by low-power machines.”

Process of generating a sufficient number of positioning commands for the servomotors driving the machine tool so the path of the tool closely approximates the ideal path. See CNC, computer numerical control; NC, numerical control.

A bit of common sense comes into play here – sticking a weighty device with a large surface area on the roof of van that could be travelling at 100 kilometres an hour, subjected to vibration and with air flow above and below the panel would suggest careful thought regarding fixing is required. This is really a job for a professional.

Image

Download the first chapter of The Good Solar Guide, authored by SolarQuotes founder Finn Peacock, FREE! You’ll also start receiving the SolarQuotes weekly newsletter, keeping you up to date on all the latest developments on Australia’s solar scene.

Did you even read my posts where I have said the 2nd panel is immovable, and the first panel’s adhesive is still attached?

Studies by YG-1 Tool (USA) showed that end users either used only one side of a double-sided, high-feed insert or accepted that they would obtain only 60% to 80% of the tool life for the second side compared with the first side when they used both sides, Andersson said.

One shift for tool manufacturers is a result of a change not in customer relationships but the climate. As the automotive industry transitions from internal combustion engines to electric motors, Keith Carlile at Iscar said toolmakers will find more competition for cobalt, a key ingredient in both carbide cutting tools and lithium-ion batteries. He predicts that cutting tools will need to be designed to help conserve carbide while more emphasis will be placed on recycling the hard metal.

I’m sure the following NSW regulation about adding fittings that are not original manufacture equipment would be covered by this RMS document to warrant its roadworthiness.

Customers additionally are looking for new avenues to partner and integrate with tool suppliers, said Robert Bokram at Ceratizit USA.

Bokram said the more robust geometry permits the double-sided inserts to have an expanded range of applications beyond finishing, including medium and roughing operations, as well as machining heat-resistant superalloys and titanium.

“This means that high-feed designs are useful for long-reach applications because they generate very little vibration,” he said. “They also minimize radial force stresses on the spindle.”

As indexable inserts evolve over time, so does a toolmaker’s relationship with its customers — sometimes fairly abruptly. Jan Andersson at YG-1 Tool (USA) said there’s been a paradigm shift over the past decade or so in how tool suppliers interact with customers as the metalcutting sector has transitioned from having one manufacturing engineer per production line or work cell and all machines being run by machinists to having one manufacturing engineer overseeing the facility as machine operators replace machinists.

For example, there are quite a few DIY videos on YouTube showing adhesive-only installations for mounting brackets, forgoing also mechanically fixing the brackets with screws.

“They can handle heavier depths of cut and higher feed rates than conventional positive designs due to better support in the pocket,” he said.

“Unlike pos/pos single-sided insert designs, they cannot perform ramping, plunging or contouring,” he said. “But they are well suited for face and shoulder milling, depending on the approach angle of the cutter.”

In numerical-control applications, a cut shorter than the programmed cut resulting after a command change in direction. Also a condition in generated gear teeth when any part of the fillet curve lies inside of a line drawn tangent to the working profile at its point of juncture with the fillet. Undercut may be deliberately introduced to facilitate finishing operations, as in preshaving.

Angle between the side-cutting edge and the projected side of the tool shank or holder, which leads the cutting tool into the workpiece.

Sadly, recommending mechanical fixing of solar panels to the caravan roof is silly. The average caravan roof is made of a sheet of 1mm or less thick sheet of aluminium, a self taping screw is not going to hold anything much into a base material like that. A very well known motorhome manufacturer, Avida previously known as Winnebago Australia, have a rubber sheet membrane over am extremely thin sheet of 3 ply with polystyrene foam under that and the inside ceiling is a sheet of aluminium ….. unless the bolts went right through all those layers and could have a nut and washer fitted where the load could be spread, mechanical or adhesive fastening will not hold a solar panel securely on these roofs. Others have fibreglass panel roof material, about 2 layers thick, and I can assure you that a self taping screw will not hold the panels on that either …. I’m in the process of fixing one right now. Silicon seals holes and does that rather poorly, it does not glue things down very well at all. Poor preparation of the surface makes the adhesion even worse. The glue of choice is an SMP type adhesive, not affected by ultraviolet light and has a high temperature adhesion point. The aluminium roof or fibre glass roof requires a good adhesion area for the SMP adhesive to stick and we recommend full length aluminium angle with a foot minimum width of 25mm, both faces roughed up to key the faces, cleaned up with the appropriate solvent, that allowed to dry and a good bead of adhesive applied that will spread out under the contact area and bead out along the edges, apply weight evenly along the contact face for 24hrs to allow a good cure thickness. It will take 7 days or more to fully cure, so high speed trips is not recommended inside the week, but the cured material will hold the uncured material in place without the weights still being required.

Michael caught the solar power bug after purchasing components to cobble together a small off-grid PV system in 2008. He's been reporting on Australian and international solar energy news ever since.

Angle of inclination between the face of the cutting tool and the workpiece. If the face of the tool lies in a plane through the axis of the workpiece, the tool is said to have a neutral, or zero, rake. If the inclination of the tool face makes the cutting edge more acute than when the rake angle is zero, the rake is positive. If the inclination of the tool face makes the cutting edge less acute or more blunt than when the rake angle is zero, the rake is negative.

High-feed indexable insert milling tools are also widely available to up throughput. Andersson said this started several decades ago with round inserts, which have a continuously variable lead angle, depending on the DOC in relation to the radius.

Robert Bokram, product manager for cutting tools at Ceratizit USA Inc. in Warren, Michigan, said toolmakers can offer double-sided milling inserts that have negative clearance geometries and high-positive rake angles.

“The exception is when the depth of cut exceeds the standard value and engages the adjacent edge, including the wiper on that edge,” he said. “Then, lower surface quality can be expected. This can be addressed with the addition of a wiper insert into one of the pockets.”

The question is what do caravan manufacturers think of this? Do they allow it that it meets the structural integrity of the frame?

Another question is, will insurance cover you for property damage and/or personal injury if the solar panel came off. It would be scrutinised with a fine tooth comb and one.

“With the increasing number of home handymen doing their own work and so many social media sites often giving suspect advice from unqualified people, it is important that handymen do their research on the correct way and safely to attach their solar panels.”

Metal-removing edge on the face of a cutter that travels in a plane perpendicular to the axis. It is the edge that sweeps the machined surface. The flat should be as wide as the feed per revolution of the cutter. This allows any given insert to wipe the entire workpiece surface and impart a fine surface finish at a high feed rate.

The use of the correct adhesive and proper surface preparation is the important part, the attaching force can often be greater than any mechanical fastener could achieve.

In addition, Romlin said rough milling with a round insert limits the ability of the tool to machine a shoulder, leaving a large scallop to be removed in a subsequent operation. He said the strategy for roughing with round inserts often involved starting with a large cutter and following with maybe two smaller inserts to rough a part.

Carlile said one benefit is an increase in the cross-sectional thickness of the insert to permit more aggressive cutting than past products and provide adequate space for including Iscar’s signature dovetail clamping configuration on the top of the insert. The dovetail traps the insert rigidly in the pocket and takes pressure off the screw, he said.

Romlin said there is also a movement away from having a large inventory of tools with different variances. Instead, tool manufacturers must produce cutting tool designs and grades that are suitable for a broader window of applications than in the past.

I contacted Selleys about the incident, and told them it was ABS mounts, so hopefully they will update the info on the cartridges and on-line. It does say to test first, so maybe I should have bought an extra mount and tried it out on the caravan first.

Maybe the manufacturers should add some stucture in the roof. Not going to be easy, there’s so many different size panels available.

The Winnebago Australia/Avida roof design requires a special frame assembly to mount the panels above the roof but tied to the 40mm sq tube that runs up each side of the roof and this will tie the solar frame and panels to the body frame. As for the 4 square corners to hold the panel on, there are also straight mounting designed to go along the straight edges of the panel and they should be used in multiples to increase the adhesion contact area, proper preparation and an SMP glue will attach these to the roof. For those with the floating skin roof, you need to find the timber bearers under the roof and attach the mounting to that, preferably by drilling a hole and sqirting a quantity of SMP adhesive to hold the roof to the timber frame under it, but if you must, a wood screw into the frame, lot of SMP adhesive to hold it in place and keep the water out will secure the mounting to the actual frame.

Strip or block of precision-ground stock used to elevate a workpiece, while keeping it parallel to the worktable, to prevent cutter/table contact.

“In order to increase the chip thickness to the ‘normal’ range for the insert edge geometry, the feed rate (ipm) must be increased,” he said. “The result is higher cutting speeds and ultimately higher metal removal rates.”

“Self-learning functions optimize real-time operations with adaptive control limits based on actual machining and tooling conditions,” he said, “so each machine can adaptively adjust machining parameters to operate at optimal conditions.”

Bokram said a common application for high-feed mills is helical interpolation, in which the high metal removal rate provides a fast, economical way to produce a large-diameter hole or counterbore, though more slowly than an appropriately sized drill.

In addition to square inserts with eight cutting edges and octagon inserts with 16 edges, Carlile said Iscar offers the H606 double-sided round insert with six total edges. The insert gives adequate room for a helix angle on the outer diameter to supply a shearing rather than a pounding cutting action. He said an undercut feature on the bottom of the insert bisects a chip and reduces the amount of force it takes to remove the chip.

I hope someone with a science background comes on here to back up my alarm as normally I am one of the last people to be alarmist except when safety is concerned. The fact that a serious accident (3 deaths) occurred in Tasmania should be enough for every regulatory authority in Australia to insist on solar panel mount safety inspections for every vehicle with them attached and help stamp out the back-yard DIY-selfers with their tubes of Bunnings silicones and glues.

Image

“For instance,” he said, “we can lay an insert negatively in the pocket with an additional dovetail to make a very strong, robust mount but still have enough carbide so that we can bring the cutting edge positive and have a positive clearance underneath.”

David Romlin, corporate product manager for indexable milling tools at Seco Tools AB in Fagersta, Sweden, said a time-tested double-sided insert is the Double Octomill, which has eight cutting edges per side for facemilling operations. (Seco Tools LLC is in Troy, Michigan.) A more recent development is the Double Turbo square shoulder mills that accept inserts with four cutting edges, which have an 11-degree positive helix angle to reduce power consumption.

Any machining process used to part metal or other material or give a workpiece a new configuration. Conventionally applies to machining operations in which a cutting tool mechanically removes material in the form of chips; applies to any process in which metal or material is removed to create new shapes. See metalforming.

“You have to look at the entire process to drive down production costs,” Andersson said. “You can’t pick tooling in a vacuum. When you are talking about new technologies, it all comes down to how you build new technology into your new release or product to aid not only in having the right speed and maximum chip control, but the absolute key part is predictability.”

This incident was widely publicised, but it doesn’t look as though all caravan owners have heeded the message. A couple of days prior to Xmas, a video was uploaded to AussieCams showing dashcam footage of a solar panel coming adrift  from the roof of a caravan near Eastern Creek in Western Sydney on December 20.

Bokram said high-feed milling tools use a simple design feature to fundamentally change machining parameters, often resulting in significantly higher total metal removal rates than conventional 45- and 90-degree designs. By reducing the approach angle of the cutter to 15 to 20 degrees, the resultant average chip thickness is reduced, which commonly is known as chip thinning.

Accidents don’t just “happen”, they are caused. Aside from the tragedy through potential loss of life or injury and the costs of damage involved, a solar panel not properly affixed and coming adrift could land the caravan owner in legal hot water as well.

Come to think of it, roof racks are mechanically fixed to the roof of car. I’ve seen solar panels fixed to the roof racks. Why can the same be applied to caravans?

Space provided behind a tool’s land or relief to prevent rubbing and subsequent premature deterioration of the tool. See land; relief.

But when advertisers, mounting bracket manufacturers, YouTubers and others continue to provide bad advice, addressing the issue of caravan solar panel safety will be difficult and no doubt further close calls – and tragedies – will occur.

Let’s face it, if the pressures were as extreme as you are trying to make out, the RV would explode into splinters as soon as a truck passed in the opposite direction …. and I’m sure you have seen the news footage of caravans that have rolled over, the strength of the frame is fairly obvious by the way they turn into a pile of match sticks when the hit the ground, so there are a lot of other structural forces involved that you have not considered. What must be noted is, not many moulded panel mounts can be glued straight onto the roof, they need a lot of preparation to get a good keyed surface for the adhesive to hold onto, the slick shiny surface does not provide that.

I find it hard to believe you can’t find any structural anchor point. But even if that were true then it would simply be a matter of building an anchor point frame inside the vehicle to bolt into from the outside. As to references for the aerodynamics I don’t have time to go searching for studies specifically for caravans and RV’s but simple common sense tells you that when you force air over the side of an object then forces will be employed. Try reading about Jayco’s solution along the lines I just suggested. . https://www.caravancampingsales.com.au/editorial/details/caravan-solar-panel-fixture-warning-126938/

I would be interested to read of the forces involved. Have any links? I can’t see the panel having lift anything like an aeroplane, otherwise wings would be made flat, with blunt leading edges.

This is frightening stuff. If the footage doesn’t make the bowels of owners of caravans with solar panels installed go all watery and inspire them to immediately check their vans (after a quick trip to the toilet), I don’t know what will.

1. Real names are preferred - you should be happy to put your name to your comments.2. Put down your weapons.3. Assume positive intention.4. If you are in the solar industry - try to get to the truth, not the sale.5. Please stay on topic.

Carlile said cutting with a round insert generally generates chips that are too thin to absorb enough heat, with the remainder going into the part and tool.

“Making a thicker insert allowed us to accept that flank wear but without having the encroachment issue,” he said. “This means four true cutting edges.”

Andersson said YG-1 Tool’s high-feed cutter has a 10-degree lead angle, which directs almost all the cutting forces into the spindle.

“If the machine can’t do linear travel fast enough,” Carlile said, “just increase your lead angle and take a deeper depth of cut.”

However, limitations exist for inserts with edges on both sides. For example, Romlin said there’s a trade-off in productivity for double-sided inserts because the number of teeth in the cutter is slightly lower than for single-sided inserts.

Imagine being the owner of that caravan and arriving at your destination to discover the solar panel was gone. There would (or at least should) be some sleepless nights to follow.

Double-sided inserts have a long history in metalcutting of reducing the cost per cutting edge, but cutting tool manufacturers continue to refine them and introduce offerings. Vernon Hills, Illinois-based YG-1 Tool (USA) Co., for example, announced that its new ENMX09 double-sided inserts have a total of four cutting edges and are suitable for high-feed milling.

There are plenty of caravans on the roads these days and many have solar panels on their roofs – but not all of these panels are properly affixed. This can result in disaster.

“They are seeking ways to integrate Industry 4.0 technologies to expand the automatization of machining functions and eliminate manual intervention,” he said. “This requires the digitalization of multiple machining functions and the capacity to provide reliable technical support remotely, especially in today’s environment where plant access might be hindered by company policies surrounding employee safety.”

Automating functions like process and tool wear monitoring, tool failure and collision detection, and adaptive feed control can reduce tool costs, tool breakages, scrap and overloads, Bokram said, noting that Ceratizit offers ToolScope for doing those tasks and more.

Caravan manufacturers will need to incorporate additional structural support in the frames to allow solar panels to be affixed correctly.

“They don’t want to have any technical question marks in terms of indexing and handling the tools,” he said. “They want to do that with limited instructions. That is a challenge to provide safe solutions where you cannot make mistakes.”

The movement away from rough milling with round inserts to high-feed milling reduced the required size and number of cutters, as well as the size of the remaining corner scallop, he said.

Developments in production technology have enabled tool manufacturers to increase the capability of double-sided inserts. Arlington, Texas-based Iscar USA, for instance, employs pressing technology with multiple stamping heads to increase the complexity of its double-sided inserts, said Keith Carlile, national product specialist for milling, who’s based in Centralia, Washington.

Machining operation in which metal or other material is removed by applying power to a rotating cutter. In vertical milling, the cutting tool is mounted vertically on the spindle. In horizontal milling, the cutting tool is mounted horizontally, either directly on the spindle or on an arbor. Horizontal milling is further broken down into conventional milling, where the cutter rotates opposite the direction of feed, or “up” into the workpiece; and climb milling, where the cutter rotates in the direction of feed, or “down” into the workpiece. Milling operations include plane or surface milling, endmilling, facemilling, angle milling, form milling and profiling.

Spoilers on cars/trucks are not glued on with adhesive, they’re bolted on. How would it be different for solar panels on caravans?

Back in October last year, we reported on a tragedy where three people died and four more were hospitalised after a driver lost control near Ross in Tasmania’s Midlands when trying to avoid a solar panel dislodged from a caravan.

“The ‘pos/neg’ pocket orientation allows for insert designs that double the number of cutting edges per insert, utilizing higher rake angle chipbreaker geometries to compensate for the negative pocket orientation,” he said. “These more robust designs have proven to be very soft cutting, demonstrating similar spindle torque values to the conventional ‘pos/pos’ milling cutter designs.”

“You gain a lot of stability compared to a 90-degree shoulder mill where the forces are predominantly radial, causing greater stress on the spindle and risking vibration issues,” he said.

“In the end,” he said, “the user must calculate the comparative metal removal rates to alternative milling system designs, based on the milling operations they are performing.”

Use of the correct adhesive is very important. I installed 2 solar panels last year, one was attached with MarineFlex, the other with ArmourFlex. Both have ABS corner & side brackets. After that first incident, I checked my panels, and found the first one was starting to lift on one corner. I had to pull up hard, but it did come off. The second panel wouldn’t budge, I even tried with a crowbar.

I don’t know if you’ve ever owned a caravan, or seen inside one. But the idea of having a “anchor point frame inside the vehicle to bolt into from the outside” is just not going to happen. Stuff like that needs to be incorporated at build time.

But it’s not just social media providing bad advice. When researching for the previous article on this issue, I came across a number of Australian web sites advertising solar panel corner mounting brackets for caravans claiming the brackets can be safely affixed using just a good quality silicone sealant/adhesive. A quick search this morning found this to still be the case.

Tools and techniques, however, are available to further reduce production costs and the cost per cutting edge when using indexable inserts. This article covers double-sided inserts and high-feed indexable insert milling tools.

In response, cutting tool manufacturers had to focus on developing products that deliver a high level of reliability, predictability and user-friendliness for part manufacturers, said David Romlin at Seco Tools.

Increasing the feed rate achieves this objective. Having wiper geometry on each cutting edge to improve surface finish enables end users to have the option of increasing the feed while maintaining the same surface finish as a conventional geometry, Bokram said. All Ceratizit USA positive/negative double-sided inserts have its Masterfinish wiper geometry on each edge.

Indexable insert tools enable manufacturers to machine parts with carbide and other hard materials without having to purchase a solid cutting tool made of the same material as the cutting edges — a progressively expensive proposition as tool diameter increases.

Loosely, any milling tool. Horizontal cutters take the form of plain milling cutters, plain spiral-tooth cutters, helical cutters, side-milling cutters, staggered-tooth side-milling cutters, facemilling cutters, angular cutters, double-angle cutters, convex and concave form-milling cutters, straddle-sprocket cutters, spur-gear cutters, corner-rounding cutters and slitting saws. Vertical cutters use shank-mounted cutting tools, including endmills, T-slot cutters, Woodruff keyseat cutters and dovetail cutters; these may also be used on horizontal mills. See milling.

Reg Watson, your knowledge of the RV industry appears to be lacking. There is nothing in the frame of the average caravan that could be bolted to that would give you the mechanical fasting you seem to consider a minimum requirement. Caravans are built from the inside out so the last thing attached is the outer skin. they are built this way so all the cabling and pipe work can be run through the walls. There is no access to the underside of the frame. The frame is either 10mm thick x 20mm wide pine, 1 mm tick aluminium tube or cold room wall panel construction that is two bits of thin aluminium sheet attached to a thick piece of polystyrene, there is nothing to bolt to and if you were to drill holes in the aluminium tube you are likely to cause the tube to crack at the fault line you have made causing the whole structure to be weakened. Adhesives have come a long way, so far that many high performance vehicle frames and chassis are actually glued together, The roof panel and front/rear windows in most production vehicles are glued on these days. The high speed trains have their panels glued on because the flexing and stresses would tear the panels around the mechanical fasteners. Adhesives add a level of elasticity that a mechanical fastener can not and that is why mechanical fasteners are not suitable for every application.

(Editor’s note: The lead angle is the angle between the side-cutting edge of the insert and the line parallel to the axis of rotation while the approach angle is the angle between the side-cutting edge of the insert and the line perpendicular to the axis of rotation.)

My caravan came with wiring, and junction box on the roof, installed ready for solar, unless it was for Christmas lights.

Carlile said Iscar furnishes cutters with a variety of lead angles to enable different chip thinning capabilities. The lead goes down to 9 degrees with the Mill4Feed line while a newer offering, the Logiq4Feed, has a 17-degree lead for reduced chip thinning.

Image

“It was a big improvement in process reliability, productivity and stability because the force being applied is less as you start to use the high-feed concept,” Romlin said. “This is one of our fastest-growing product areas, supporting the need for productivity improvements in the manufacturing industry. The high-feed concept is now an established machining method.”

“When it comes to cost per part, it all comes down to productivity because in reality the cost of the insert is very little in the scope of things,” Andersson said, adding that the cost of cutting tools represents on average 3% to 5% of total production costs. “You drive down production cost through productivity.”

Replaceable tool that clamps into a tool body, drill, mill or other cutter body designed to accommodate inserts. Most inserts are made of cemented carbide. Often they are coated with a hard material. Other insert materials are ceramic, cermet, polycrystalline cubic boron nitride and polycrystalline diamond. The insert is used until dull, then indexed, or turned, to expose a fresh cutting edge. When the entire insert is dull, it is usually discarded. Some inserts can be resharpened.

I don’t think a caravan is classed as a vehicle, a motorhome or campervan probably is, but a quick read of the pdf seems only to mention mechanical mods, nothing about attaching solar panels.

Probably several items already on the roof would interfere with racks, and vice versa. Panels are usually placed where there is room (unlikely I know). Mine are: one behind an AirCon, and the other a large sunroof/vent. There’s a wind up TV antenna and an ensuite vent to avoid as well.

“It’s detrimental from a technical perspective,” he said. “The one thing about double-sided inserts is you risk damaging the noncutting edge. If you don’t have chip control, the chip can wrap around and damage the bottom side of that insert.”

It needs bolting down and into a proper support structure of the caravan or RV. If you want to glue as well as an extra precaution fine but bolting down will be the minimum required.

And as I said earlier, any adhesive will degrade over time when exposed to the elements. The combination of the wind against the panel trying to lift off coupled with extreme temperature variations, mechanical vibration during transit and UV/water exposure will all conspire together to weaken the adhesive over time. It will never be a permanent solution and will need constant checking. But, it’s your responsibility if the adhesive fails and something wrong happens, what will you have to say in court/police? Blame the adhesive company?

For more information from Iscar USA about its high-feed indexable insert milling tools, view a video presentation at cteplus.delivr.com/2swtt

One more thing: I forgot to mention that the mounts came way from the adhesive, which is still firmly (mechanical removel needed) attached to the roof.

“Traditionally, manufacturing engineers were not only designing and setting up new components and new production lines, but they were also working on continuous improvement,” he said. “But if you have one manufacturing engineer for the plant, there is no time for continuous improvement. That time is spent being a firefighter.”

In addition, machine operators don’t have a journeyman machinist’s in-depth knowledge and are tasked mainly with activities, such as changing parts, pushing the start button and indexing inserts, Andersson said. In contrast, a machinist can make on-the-fly changes and tweak a process to improve it.

However, drawbacks exist. Bokram said a high-feed mill can impart poor surface finishes, so it’s applied only for roughing, and the DOCs are restricted because of the shallow approach angle.

He said the ENMX09 is 6.2 mm (0.244") thick, which compares with insert thicknesses of 4.6 mm (0.181") and 4.8 mm (0.189") for two popular competing products.

For example, Seco Tools introduced the High Feed Square Cut size 14 milling system late last year. The toolmaker reports that the single-sided, straight-edge insert geometries of the system are suitable for high-feed ramping, pocketing, plunging, facemilling and copy milling.

People the forces involved on that panel are significant and the extent depends on a multitude of factors. As well I am sure many of you have felt the significant sideways forces when passed by a big truck or perhaps seen a heavy marquee tent lifted into the air like a feather when hit by a decent wind-gust. Well that sort of force is acting on the “glue-only” installation holding your roof-mounted solar panel – not to mention the wearing daily effects of UV, salt spray, flexing of the roof etc etc etc. You think because your panel is mounted flat on the roof of your caravan or RV that it isn’t being affected by upwards wind forces ? Think again.

Groove or other tool geometry that breaks chips into small fragments as they come off the workpiece. Designed to prevent chips from becoming so long that they are difficult to control, catch in turning parts and cause safety problems.

“What makes them unique is the thickness, which addresses one of the major issues you have with double-sided, high-feed inserts,” said Jan Andersson, director of product management for indexable inserts. “The nature of the application is that you will always have flank wear on the bottom of the insert.”

This is my last word on the subject because I am shaking my head at some of the comments in this column. A self-tapping screw you were considering ? I’ll have to remember that when I install my grand-daughter’s car seat.

Form of milling that produces a flat surface generally at right angles to the rotating axis of a cutter having teeth or inserts both on its periphery and on its end face.

Runs endmills and arbor-mounted milling cutters. Features include a head with a spindle that drives the cutters; a column, knee and table that provide motion in the three Cartesian axes; and a base that supports the components and houses the cutting-fluid pump and reservoir. The work is mounted on the table and fed into the rotating cutter or endmill to accomplish the milling steps; vertical milling machines also feed endmills into the work by means of a spindle-mounted quill. Models range from small manual machines to big bed-type and duplex mills. All take one of three basic forms: vertical, horizontal or convertible horizontal/vertical. Vertical machines may be knee-type (the table is mounted on a knee that can be elevated) or bed-type (the table is securely supported and only moves horizontally). In general, horizontal machines are bigger and more powerful, while vertical machines are lighter but more versatile and easier to set up and operate.

I recognise that section of the road…. worse place for a solar panel to come off near a bridge on a 110km/h motorway (with minimum shoulders). I dare say what would have happened if a truck was there at the same time and there are lots of trucks that use that road.

Nonetheless, Bokram said that shallow approach angle causes the net resultant machining forces to be exerted mainly along the axis of the milling cutter.

“There is nothing in the frame of the average caravan that could be bolted to that would give you the mechanical fasting you seem to consider a minimum requirement.”

From what you are suggesting why on earth would you just attach a solar panel with adhesive only given you have no idea the wind forces involved that would be acting on the panel at 100 klm/hr ? The airflow over the top of the panel if exposed to wind forces is similar to that of an aircraft wing and produces reduced pressure above the panel which then has a natural tendency to lift. I don’t think Boeing rely on just glue to hold their wings to the airframe. We don’t glue solar panels to our rooves either.

Alan holds a bachelor’s degree in journalism from Southern Illinois University Carbondale. Including his 20 years at CTE, Alan has more than 30 years of trade journalism experience.