FAQ – miniMonster automation

Frequently asked questions

lemontart is simply the new model name given to the DIY assembly kits of minimonster machines. We have an article with a more in depth explanation here.

Basic assembly is fairly simple and require only a few common machinist's tools. You should get within 50 microns of squareness and have the machine assembled in 4-6 hours. Advanced assembly with granite surface plates and squares and the provided shim kits can get you to better the 20 microns squareness if you put in a few extra hours.

lemontart kits are made to order. It usually takes about 3 weeks to build the machine, and about a further week to ship. Holidays like Chinese new year will impact shipping schedules.

There a number of accessories available and planned in "downloadable" from. The include vacuum work holding plates, a 4th axis, a right angle index block, ATC and enclosures with many others in the works. The system for downloading accessory file kits is under construction, so it is best to contact miniMonster with what you need.

Not yet, but this is planned for the near future. We will have bundled kits which include combinations of accessories like the enclosure, stand and ATC and 4th axis.

"In the works" as they say. Prototypes will be tested over the next few months before release. It will be available for HSK25E tooling and mount to both the lemontart 33metal, as well as the future miniMonster 430

The lemontart 33metal will have two downloadable enclosure options. One is a simple chip pan and connections for a 3d printer type fabric enclosure. This is only suitable for non ferrous metal cutting with MQL coolant as well as plastics and wood. But it is very low cost.

The second enclosure is a full steel stand and cabin, with provisions for lighting, coolant, chip disposal and mounting the control cabinet

As the download system is under construction, please contact us to get the file project for the enclosures.

The base lemontart 33metal frame kit includes the basic machined frame components, the sheet metal guarding and bracing, and some critical 3d prints for cable management and way wipers. It includes the ball screws, linear guides, bolts, cable chains, servo motor couplings and feet for mechanical parts. All electrical is additional, as are tooling and accessory items. One important thing it does NOT include is the spindle clamp. This you download separately. The reason being that there is much to wide a variety of spindle options.

The short answer is that you need to provide all electric part, the servos, the spindle, the control. Additionally a lubrication system is recommended, but not mandatory. We will have recommended build guides, but as the website is under construction, if they are not there yet, do not hesitate to contact us.

Depending on your build and tooling choices, you may require a spindle clamp, and an air compressor and a vacuum pump.

Downloadable accessories like a 4th axis, enclosure and ATC will require their own build bill of materials.

This is a broad question. There are hundreds of options each with their own good and bad points. We will be offering a build guide for using LinuxCNC with ethercat servo systems and modbus spindle control. Linuxcnc is free, open source, and flexible. The motion system is not as advanced as professional industrial controls, but is still extremely productive. Every demo video we have show on the lemontart, and miniMonster prototypes has been run with LinuxCNC. Notably, Tormach's pathpilot control software is also LinuxCNC with a customised user interface and a few updated features.

For the most part, simple MQL (or low flow mist) are suitable for all typos of metal cutting. These can be made up of low cost parts, or bought as systems. We do not yet have a specific one to recommend, they are all kinda similar.

Flood, or future microjet high pressure coolant will be option with the full steel enclosure. Again, we have no specific system to recommend, there are many. To keep the system inside the machine enclosure it will need to be on the small side. Otherwise you can use just about any system.

As far as the actual coolant. Koolmist 78 is what we use, because it has low to no fogging. With pressurised MQL you have more coolant choices. We recommend against alcohol only because we have no data on how it plays with the various plastics, prints and seals on the machines. File it under "use at your own risk".

330mm X, 280mm Y, 130mm Z. The clean gantry clearance above the table is 133mm. It is possible to overhang parts on the front end of the machine, which allows you to machine the ends of long parts up to about 30mm deep (depending on tool diameter and work holding).

The sub table surface is 242mm wide, and 430mm long. You of course can't access the back part of the table with tools, but you can use that space to mount your index block and 4th axis to keep it out of the main work area allowing longer parts on the 4th axis, as well as not having to remove the rotary table when you need to machine in the main table area. A standard useful layout is for example the index block or 4th axis in the back right with a zero point plate on it, and then another flat mounted zero point plate in the front left. And then you put your tool setter in the back left. This lets you do 4 sided parts and second ops without needing to move workholding around.

The base miniMonster kits uses JLC hardware. The linear guides are "4 way" load 15 and 20mm sizes, with heavy preload. The ball screws are 16mm diam, 10mm pitch, precision ground, C5 grade. They have light preload.. The bearing supports are FK and EK style. This all results in precise backlash and play free motion. We use zero backlash disc spring couplings which are a dramatic improvement over the plastic spider type.

When the lemontart machines begin to be offers with localised assembly, we will also then be able to offer an upgrade kit. This will include higher quality SBC/NSK/ISSOKU brand running gear with higher precision ratings. There will be a significant price jump, but for some people the standardised readily available nature of these parts will be important for future repairs and maintenance. The additional precision of both there upgraded hardware and the pre assembly will also be a key factor for anyone doing more critical work.

For the vast majority of people however the base hardware in the kit will be more than adequate.

Note that it is entirely possible to upgrade the hardware on your lemontart at a later date.

We... don't really know. Honestly every time we have installed a bigger more powerful spindle the machine has increased it performance and reduced chatter. This isn't actually too strange because while the frame deflects under load as all machines do, "chatter" is mostly cause by the work, the cutter, and the spindle bearings. Bigger spindles have more rigid bearings.

Unfortunately there is a limit to this experiment because bigger spindle also come with more weight. Broadly speaking, you want an ISO10, ISO20, HSK25E or and 80mm ER spindle that weight 8-10kg and has less than about 1.5nm torque. More than 10kg and the inertia of the spindle begins to show in your cut as slight gouges in the floors of part at the corners, or ringing in 3D surfaces.

The baseline spindle recommendation in our guides is an 80mm 2.2kw ISO20 spindle.

60mm JIS standard. Generally you will be using 200w, or 400w ac servos.

Technically you could with an adapter for nema23, but there really is no reason to do so. AC servos are better in every way and not very expensive anymore.

Precision is complicated. And on a DIY kit frame, is even more complicated.

Let's break this down into 4 parts.

1: Squareness and flatness.

2: Motion precision.

3: Drive precision.

4: Cutting precision.

For squareness and flatness. the default expectation is 50 microns all over the machine. That means anywhere in the travel at a static position, the spindle nose is within 50 microns of where you expect it to be. With more advanced assembly, a skilled builder with the right tools should be able to bring this number down to 20 microns.

Next we get to motion precision. This is basically your ball screw and it's supports. Since our entire mechanical system is preloaded, there is no play, so we basically go by the ball screw rating. C5 on a ground screw means that the maximum deviation anywhere over 300mm is less than 18 microns.

Drive precision is where things get spicy. You can lock down your machine all you want, but if your servo motors are floppy, it won't help you. Servo performance will vary wildly, and it's not always the more expensive ones that perform better. A good new low cost ethercat servo system will maintain position AT SPEED (during acceleration) at about 8 to 18 microns. This means that during a cut, especially a curve or 3d surface, each axis motor will be somewhere between 8 and 10 microns of where there are supposed to.

And that finally brings us to the cut. You may have already figured out that all the above doesn't necessarily mean your part will be that precise. It may be worse, it may actually be better if it is a small part, because these errors are quite dependent on scale. BUT, what they do provide is a base to get the best cut you can by having no play, and predicable motion. Predictability is the most critical part. IF you can predict things, you can compensate for them, and this is exactly what we do when we cut.

You make a part, a test cut, and you measure it. then you compensate. You measure the tool diameter, you measure the deflection in your finish pass, you map the ball screws deviations over the travel. And then you compensate.

The end result is that it is entirely possible to machine a part precise to just a few microns - and it is very possible to make one out by 100, all with the same machine. High cutting precision is therefore YOUR responsibility in the end. We can only provide you with a predictable base to work with.

Both the fabric and steel enclosures ere in flux at the moment due to ATC design iterations, but will be about 750mm square. Plus or minus 30mm if if you are trying to allocate space for the machine. The sides of the machine and the rear of the machine to not need daily access, so you can put the machine in tight spaces others won't fit.

Yes, there is a small 4th axis for the lemontart 33metal coming soon. It will be both downloadable, and available assembled (minus the servo motor). This can mount in 3 spots on the machine table, back right, back middle, and front middle for overhanging parts.

The 4th axis is based on a harmonic drive with crossed roller bearings and will have under 10 arc seconds backlash, 20 arc second true position, and 22nm continuous torque. With a 100w 6000rpm AC servo it can run 30rpm continuously and 60rpm rapid indexing.

It will take a 52mm zero point plate, and for non lemontart use itself can be mounted onto a 52mm zero point plate. The total useful part/chuck/vise diameter is 120mm when used on the lemontart 33metal.

Unfortunately no. There is simply not enough clearance to make a 4 axis trunnion wok on the machine.

Zero point work holding is a concept where you place your work holding fixtures - vises, plates, vacuum chucks, even the 4th axis - onto modular base plates that index the fixture precisely. This eliminates the need to re tram/align your work holding every time you change it. It also brings in the concept of changing the VISE and not the clamped part on the machine, allowing reduced downtime. You simply have 2 or more vises that you swap out in seconds, and change the part in the vise outside the machine.

For this system to really be most efficient, vises are made small and inexpensive (as low as $50usd each) so it is cost effective to buy many - each one sized for the job it needs to do. When you have jobs needing soft or custom jaws, you don't simply store jaws on a shelf and reinstall them every time you run that part, you dedicate an entire vise to those jaws. Every time you need it you pop the part in the vise, and pop the vise into the machine's zero point base plate for milling.

The lemontart 33metal table is pre driiled for up to 2 Xindian 52mm zero point base plates. We chose them because they are cheap and reliable. Other systems are available, but every one has a different mounting pattern often, so you will need to drill new holes (or possible just have a customised table made - yes you can do that, just ask!). With the 52mm base plate you can now mount a whole host of compatible vises, chucks, pallets, etc from any vendor that supports the 52mm system. Do note that the Xindian plate uses "Lang compatible studs" when purchasing your tooling.

Not a problem, you can mount any type of fixture plate you want onto the machine using the various mounting points. Vacuum fixtures, clamping pallets are easy to mount on registration pins. You can even directly mount some vises - such as the Xindian H67 directly to the table giving 27mm extra height clearance.

Yes, we have a number of downloadable vacuum work holding accessories.

We recommend against it. The mod vise, and other 2 part vises as well as toe clamps create a bending force in whatever plate they are attached to. Usually this is a relatively thin grid fixture plate. This then gets translated into the machine table. Since the lemontart has a relatively light table, the forces from the bice could twist the frame, causing issues with precision or even linear guide misalignment.

If you do have a need for a 2 part vise for your job, make sure the fixture plate is thicker than normal - 32mm in aluminium and 25mm in steel and you use relatively light clamping pressures. measure deflection and lift when torqueing down the vise or clamps.

Yes, there will be a written and a video step by step guide for basic assembly, as well as a guide on more precise advanced assembly.

Yes, we will have 2 recommended builds - one CSA/UL approved, one lower cost option that is not - and also some other vendor options for some parts.

The lemontart 33 metal can come with a machined aluminium table, with thread inserts, OR a upgraded higher precision and more durable 4140 steel table. Unfortunately at the moment there are manufacturing issues with the aluminium table, so it is temporarily unavailable. When those issues are fixed, the table will become available, resulting in a slightly lower cost for the kit.

Quite effective. The way guarding on the lemontart machines consist of stainless steel sheet metal to deflect chips and coolant, and SLS printed nylon wipers to keep chips from getting inside certain areas.

When considering way covers, there is a general rule. Completely enclosed way covers are great, but expensive and complicated on a compact machine. But bad way covers are actually WORSE than having none at all. The reason is that chips and coolant WILL get into them eventually - bellows covers will actively suck in debris with air pressure - and when you have a full cover you tend not to look under them for long periods of time, reducing user maintenance intervals.

With simlpe guarding you can alway see the state of the mechanical, and quickly blow/brush out any chips or dirt when they are found. The guards are also easy to remove and manage when needed for deeper maintenance.

Strictly speaking, there is no warranty like you might have on a consumer electronics device. If your machine kit comes with a defective or damaged part, that part will be replaced free of charge, but if you damage a part of the machine during use or improper assembly, you will be responsible for paying for a new replacement part. ALL parts can be purchased individually for replacement. Note that some mechanical parts like rails and balls screws might change brand or appearance but the function and specification will be the same as the original.

You also generally cannot return a machine frame kit. This is mostly due to logistics. It would literally cost thousands of dollars to ship it back in some cases. if for whatever reason yoy no longer need your lemontart machine kit, you can use our discord channel to offer it to other users.

Usually, yes. You would simply need to purchase the parts that have been enhanced, and replace the old ones on the machine. We try to make enhancements and revisions fairly self contained, so you don't need to buy huge amounts of new parts just to get one small extra feature.

Lubrication can be standard grease, or oil. You can use the fitted zerks on the linear blocks for grease, along with the remote lines on the ball screws. If you want to use a remote grease or oil system, you will need to purchase the appropriate fittings for the X and Z linear blocks. Unfortunately we are not able to provide these as standard right now.

Broadly speaking, 0.1mm to 8mm. This fits in the torque range of the common spindles, and in the tool changers, and allows use of a low cost laser tool setter.

Nothing is physically stopping you from using larger cutters, just be aware of the possible effect including spindle damage from spinning tools in the taper.

The position for the tool setter is in the back left. We can help you with a downloadable "perch" for most common tool setters. The one we are going to be recommending is a laser tool setter than handles up to 8mm diameter cutters and can measure lengths and diameters with about 2 microns precision, and will not break microtools.

It depends, but most likely yes. ATC spindles almost always use air for tool release and bearing purges, and You will need it for mist or MQL coolant. Some vacuum work holding requires a strong compressor as well. We recommend having more than 2hp available. Remember when reading flow ratings, devices measure their needs as input AT rated pressure, and most compressors rate it as input at atmospheric air pressure. So a 2cfm tool at 90psi doesn't need a 2cfm compressor, it needs a 10+ cfm compressor.

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