际上，消失模铸造是一个系统工程，理论上可以用于生产各种铸件，并且在实验室取得了广泛的成功。但是，由于我国消失模铸造模型材料普遍采用包装用的泡沫聚苯乙烯(EPS)，并且专用涂料技术还没有形成技术优势，加之干砂振动技术和消失模铸造工艺也不成熟，从而导致许多初上企业，特别是中小企业对于这些认识还不深入，所以才会出现一哄而上又一哄而下的被动局面。

Internationally, lost foam casting is a systems engineering that can theoretically be used to produce various castings and has achieved widespread success in the laboratory. However, due to the widespread use of foam polystyrene (EPS) for packaging as the EPC model material in China, and the lack of technical advantages in special coating technology, as well as the immature dry sand vibration technology and EPC process, many start-up enterprises, especially small and medium-sized enterprises, have not yet deepened their understanding of these issues, so there will be a passive situation of crowding up and down.

那么消失模铸造技术在我国真的没有发展前景吗？答案是否定的。通过十多年的生产实践，我国采用消失模技术进行铸造生产的企业，已由开始阶段不到十家发展到目前的数百家就是一个有力的证明。消失模铸造生产在我国有许多成功的实例，没有达到预期效果而下马的企业也有相当多的数 铁艺栏杆福特铁艺 量。分析成功的经验和失败的教训，对于消失模铸造在我国的发展前景，关键在于对这种工艺的认知程度，在于对该工艺生产系统的优化控制，包括对原材料、涂料技术、干砂紧实技术以及消失模铸造工艺技术的优化控制等。

So does lost foam casting technology really have no development prospects in China? The answer is negative. Through more than ten years of production practice, it is a strong proof that the number of enterprises in China that adopt lost foam casting technology for casting production has grown from less than ten in the initial stage to hundreds at present. There are many successful examples of lost foam casting production in China, and there are also a considerable number of companies that have not achieved the expected results and have fallen from business. Analyzing successful experiences and lessons learned from failures, the key to the development prospects of lost foam casting in China lies in the level of understanding of this process and the optimization control of the production system, including raw materials, coating technology, dry sand compaction technology, and lost foam casting process technology.

一、原材料的优化控制

1、 Optimization control of raw materials

消失模铸造生产需要的原材料大致分为模型原材料、干砂原材料、涂料原材料、合金熔炼原材料等几个方面。由于消失模铸造工艺是一项系统工程，原材料的选择尤为重要。所以控制各种原材料的质量和参数就成了消失模铸造成败的基础。

The raw materials required for lost foam casting production can be roughly divided into several aspects, such as model raw materials, dry sand raw materials, coating raw materials, and alloy melting raw materials. Due to the fact that the lost foam casting process is a systematic engineering, the selection of raw materials is particularly important. So controlling the quality and parameters of various raw materials has become the foundation for the success or failure of lost foam casting.

模型材料通常称之为珠粒，铸造上采用的珠粒一般分为两种类型，即聚苯乙烯(PS-Polystyrene)珠粒和聚甲基丙烯酸甲酯(PMMA-Polymethyl Methacrylate)珠粒，二者都属于高分子材料 铸铁围墙福特铁艺 。另外还有一种PS+PMMA的聚合物。对于低碳钢铸件，模型材料中的碳易使铸件表面产生增碳现象，从而导致各种碳缺陷。其中PS(含碳92％)、PS＋PMMA共聚物、PMMA(含碳60％)对铸件的增碳影响程度依次减小。此外，模 型的密度是其发气量的重要控制参数，上述三种材料的发气量从小到大依次为PS、PS＋PMMA共聚物、PMMA。同时，珠 铁艺围墙福特铁艺 粒的尺寸应根据所生产铸件的壁厚进行选择，一般情况下，厚大铸件选用较粗粒径的珠粒，反之薄壁铸件选用较细粒径的珠粒，使铸件薄部位保持三个珠粒以上为宜。

The model material is usually referred to as beads, and the beads used in casting are generally divided into two types, namely polystyrene (PS polystyrene) beads and polymethyl methacrylate (PMMA polymethyl methacrylate) beads, both of which belong to the polymer material cast iron fence Ford iron art. There is also a polymer of PS+PMMA. For low-carbon steel castings, the carbon in the model material can easily cause carbonization on the surface of the casting, leading to various carbon defects. Among them, PS (containing 92% carbon), PS+PMMA copolymer, and PMMA (containing 60% carbon) have a decreasing effect on the carbonization of castings in sequence. In addition, the density of the model is an important control parameter for its gas generation, and the gas generation of the three materials mentioned above are PS, PS+PMMA copolymer, and PMMA in descending order. At the same time, the size of the bead iron fence Ford iron particles should be selected according to the wall thickness of the produced castings. Generally, thicker castings should use coarser particle size beads, while thinner castings should use finer particle size beads, so that the thin part of the casting can maintain at least three beads.

另外，模型材料的预发和成形控制也 铸铁护栏 是技术成功的一个关键。一般情况下，预发珠粒其密度控制在约0.024～0.03g/cm3，其体积约为原珠粒体积的30倍。成形 铸铁栏杆 模型的密度控制在约0.02～0.025g/cm3。

In addition, the pre production and forming control of model materials are also key to the technical success of cast iron guardrails. In general, the density of pre packaged beads is controlled at about 0.024-0.03g/cm3, and their volume is about 30 times that of the original beads. The density of the formed cast iron railing model is controlled at about 0.02-0.025g/cm3.

干砂是消失模铸造的造型材料，由于该工艺的特点 ，选择干砂应与生产的铸件材质有关，高温合金采用耐火度较高、颗粒较粗的干砂。目前干砂主要使用天然石英砂，应去除砂中的铁渣、粉尘和水分，并保持使用温度不高于50℃。

Dry sand is the molding material for lost foam casting. Due to the characteristics of this process, the selection of dry sand should be related to the material of the castings being produced. High temperature alloys use dry sand with higher refractoriness and coarser particles. At present, natural quartz sand is mainly used for dry sand. The iron slag, dust, and moisture in the sand should be removed, and the operating temperature should not exceed 50 ℃.

涂料是消失模铸造中必不可少的原料，现在许多铸造厂采用自制涂料。涂料的主要作用是提高模型的强度和刚度、防止破坏或变形；隔离金属液和铸型；排除模型气化产物；保证铸件表面质量等。消失模涂料中耐火骨料主要有锆英粉、铝矾土、棕刚玉粉、石英粉、滑石粉、莫来石粉、云母粉等。其粒径级配应兼顾防止粘砂和高温透气性，粒形有利于提高透气性，通常选择一定数量的球状颗粒，有利于模型气化后气体的逸出或模型不完全分解的液化产物的排除。

Coatings are essential raw materials in lost foam casting, and many foundries now use homemade coatings. The main function of paint is to improve the strength and stiffness of the model, prevent damage or deformation; Isolate metal liquid and mold; Exclude gasification products from the model; Ensure the surface quality of castings, etc. The refractory aggregates in lost foam coatings mainly include zircon powder, bauxite, brown corundum powder, quartz powder, talc powder, mullite powder, mica powder, etc. The particle size distribution should take into account the prevention of sand sticking and high temperature permeability. The particle shape is conducive to improving permeability. Usually, a certain number of spherical particles are selected, which is beneficial for the escape of gas after gasification or the elimination of liquefied products from incomplete decomposition of the model.

二、涂料制配的控制

2、 Control of coating preparation

消失模铸造涂料的载体多采用水基，以利于环境保护。其粘接剂主要包括粘土、水玻璃、糖浆、纸浆废液、白乳胶、硅溶胶等。在选择粘接剂考虑以下几个方面因素：高温发气性；涂挂性；涂层强度和刚度；浸蚀模型性等。悬浮剂用于防止涂料发生沉积、分层、结块，使涂料具有触变性。一般可采用膨润土、凹凸棒石粘土、有机高分子化合物及其复合体等。另外消失模涂料中还需添加表面活性剂，以增加涂料的涂挂性，提高涂料与模型表面的亲和性和结合强度。此外还常常加入其他添加剂，如消泡剂、减水剂、防腐剂、颜料等。

The carrier of lost foam casting coatings is mostly water-based, which is beneficial for environmental protection. The adhesive mainly includes clay, water glass, syrup, pulp waste liquid, white latex, silica sol, etc. When choosing an adhesive, the following factors should be considered: high temperature gas generation; Coating property; Coating strength and stiffness; Etching modeling, etc. Suspension agents are used to prevent sedimentation, delamination, and agglomeration of coatings, giving them thixotropy. Generally, bentonite, attapulgite clay, organic polymer compounds, and their composites can be used. In addition, surfactants need to be added to the lost foam coating to increase the coating's adhesion, improve the affinity and bonding strength between the coating and the model surface. In addition, other additives such as defoamers, water reducers, preservatives, pigments, etc. are often added.

为此，要求涂层具有良好的强度、透气性、耐火度、绝热性、耐急冷急热性、吸湿性、清理性、涂挂性、悬浮性等。综合起来主要包括工作性能和工艺性能。

Therefore, it is required that the coating has good strength, breathability, fire resistance, thermal insulation, resistance to rapid cooling and heating, moisture absorption, cleaning, coating, suspension, etc. Overall, it mainly includes work performance and process performance.

涂料的工作性能包括强度、透气性、耐火度、绝热性、耐急冷急热性等，主要是在浇注和冷却过程中应具有的性能，其中重要的是强度和透气性。而涂料的工艺性能包括涂挂性、悬浮性等，主要是在涂挂操作中所要求的性能。

The working performance of coatings includes strength, breathability, fire resistance, insulation, and resistance to rapid cooling and heating, which are mainly the properties that should be possessed during pouring and cooling processes, among which strength and breathability are important. The process performance of coatings includes coating and suspension properties, mainly the performance required during coating and suspension operations.

一般消失模铸造多采用水基涂料，涂料与模型一般不润湿，从而要求改进水基涂料的涂挂性。涂挂性是指模型涂挂涂料后一般需要悬挂干燥，希望涂料在涂挂后尽快不滴不淌，确保涂料层的均匀性，减少环境污染。悬浮性是指涂料在使用过程中，涂料保持密度的均匀性，不发生沉积现象。

Generally, water-based coatings are commonly used in lost foam casting, and the coating and model are generally not wetted, thus requiring improvement in the coating properties of water-based coatings. Coating adhesion refers to the general need for the model to be hung and dried after coating, with the hope that the coating will not drip or drip as soon as possible after coating, ensuring the uniformity of the coating layer and reducing environmental pollution. Suspension refers to the uniformity of density maintained by the coating during use, without any sedimentation phenomenon.

涂料的制配工艺控制是涂料技术的关键环节。国产涂料多采用碾混、辊混或搅拌工艺。根据生产实践，碾混和辊混其质量优于搅拌。建议有条件的企业可采用碾混或辊混方法制配涂料。

The control of coating preparation process is a key link in coating technology. Domestic coatings often use rolling, rolling, or mixing processes. According to production practice, the quality of grinding and roller mixing is better than that of mixing. It is recommended that companies with conditions can use the rolling or roller mixing method to prepare coatings.

由于不同的合金对涂料的作用情况不同，建议根据合金种类的不同研制相应的涂料，如铸铁涂料、铸钢涂料、有色合金涂料等。在涂料配置和混制过程中，应尽量使用合理的骨料级配，使骨料和粘接剂及其它添加剂混合均匀。

Due to the different effects of different alloys on coatings, it is recommended to develop corresponding coatings based on the type of alloy, such as cast iron coatings, cast steel coatings, non-ferrous alloy coatings, etc. In the process of coating preparation and mixing, reasonable aggregate gradation should be used as much as possible to ensure uniform mixing of aggregates, adhesives, and other additives.

除了涂料性能达到要求外，涂敷和烘干工艺对生产也具有一定影响。生产上多采用浸涂，好是一次完成。也可以分两次涂敷，但应每次涂敷后要进行烘干，烘干时注意烘干温度的均匀性和烘干时间，保证涂层干燥彻底并不开裂。

In addition to meeting the requirements for coating performance, the coating and drying processes also have a certain impact on production. Dip coating is often used in production, which is better done in one go. It can also be applied twice, but it should be dried after each application. When drying, pay attention to the uniformity of drying temperature and drying time to ensure that the coating is completely dried and does not crack.

三、干砂造型工艺的控制

3、 Control of dry sand molding process

干砂造型是将模型埋入到砂箱中，在振动台上进行振动紧实，保证模型周围干砂充填到位并获得一定的紧实度，使型砂具有足够的强度抵抗金属液的冲击和压力。

Dry sand molding is the process of embedding a model into a sand box and compacting it on a vibration table to ensure that the dry sand around the model is filled in place and a certain degree of compaction is obtained, so that the molding sand has sufficient strength to resist the impact and pressure of the molten metal.

干砂造型步是向砂箱中加入干砂，加砂时为保证干砂的充填到位，首先在砂箱中加入一定厚度的底砂并振动紧实，然后放入模型簇，再加入一定厚度的干砂，将模型簇埋入到三分之一到二分之一，再进行适当振动，以促使干砂向模型内腔充填。后填满砂箱进行振动，振动时间不宜过长，以保证模型不出现损坏和变形，同时保证涂料层不发生脱落和裂纹。

The step of dry sand molding is to add dry sand to the sand box. To ensure that the dry sand is filled in place, a certain thickness of bottom sand is first added to the sand box and compacted by vibration. Then, a model cluster is placed, and a certain thickness of dry sand is added to bury the model cluster to one-third to one-half, and appropriate vibration is carried out to promote the filling of dry sand into the interior of the model. After filling the sand box, vibration should not be carried out for too long to ensure that the model is not damaged or deformed, and that the coating layer does not peel off or crack.

振动参数应根据铸件结构和模型簇形式进行选择，对于多数铸件，一般应采用垂直单向振动，对于结构比较复杂的铸件，可考虑采用单向水平振动或二维和三维振动。振动强度的大小对干砂造型影响很大，用振动加速度表示振动强度。对于一般复杂程度的铸件和模型簇，振动加速度在10～20m/s2之间。而振幅是影响模型保持一定刚度的重要振动参数，消失模铸造振幅一般在0.5～1mm。振动时间的选择比较微妙，应结合铸件和模型簇结构进行选择。但总体上振动时间约控制在1～5min为宜。同时底砂、模型簇埋入一半时的振动时间尽量要短，可选择1～2min，模型簇全部埋入后的振动时间一般控制在2～3min即可。

The vibration parameters should be selected based on the casting structure and model cluster form. For most castings, vertical unidirectional vibration should generally be used. For castings with complex structures, unidirectional horizontal vibration or two-dimensional and three-dimensional vibration can be considered. The magnitude of vibration intensity has a significant impact on dry sand molding, and vibration acceleration is used to represent vibration intensity. For castings and model clusters of general complexity, the vibration acceleration is between 10 and 20m/s2. And amplitude is an important vibration parameter that affects the model to maintain a certain stiffness, and the amplitude of lost foam casting is generally between 0.5-1mm. The selection of vibration time is delicate and should be based on the casting and model cluster structure. But overall, it is advisable to control the vibration time within 1-5 minutes. At the same time, the vibration time when the bottom sand and model clusters are buried in half should be as short as possible, and 1-2 minutes can be selected. The vibration time after burying all the model clusters is generally controlled at 2-3 minutes.

四、铸造工艺的控制

4、 Control of Casting Process

消失模铸造工艺包括浇冒口系统设计、浇注温度控制、浇注操作控制、负压控制等。

The lost foam casting process includes the design of sprue and riser systems, pouring temperature control, pouring operation control, negative pressure control, etc.

浇注系统在消失模铸造工艺中具有十分重要的地位，是铸件生产成败的一个关键。在浇注系统设计时，应考虑到这种工艺的特殊性，由于模型簇的存在，使得金属液浇入后的行为与砂型铸造有很大的不同。因此浇注系统设计必定与砂型铸造有一定的区别。在设计浇注系统各部分截面尺寸时，应考虑到消失模铸造金属液浇注时由于模型存在而产生的阻力，小阻流面积应略大于砂型铸造。

The pouring system plays a very important role in the lost foam casting process and is a key factor in the success or failure of casting production. When designing the pouring system, the particularity of this process should be taken into account. Due to the presence of model clusters, the behavior of the molten metal after pouring is significantly different from that of sand casting. Therefore, the design of the pouring system must have certain differences from sand casting. When designing the cross-sectional dimensions of each part of the pouring system, consideration should be given to the resistance generated by the presence of the model during the pouring of the lost foam casting metal liquid. The small flow resistance area should be slightly larger than that of sand casting.

由于铸件品种繁多、形状各异，每个铸件的具体生产工艺都有各自的特点，并且千差万别。这些因素都直接影响到浇注系统设计结果的准确性。为此，可将铸件以某种方式进行分类。针对中小铸件，可按铸件生产工艺特点进行分类，如表1所示。模型簇组合方式可基本反映铸件的特点，以及铸件的补缩形式。浇注系统各部分截面尺寸与铸件大小、模型簇组合方式以及每箱件数都有关系。为此，在设计新铸件的工艺时，应根据铸件特征，参照同类铸件浇注系统特点有针对性地进行计算。

Due to the wide variety and diverse shapes of castings, each casting has its own unique production process and varies greatly. These factors directly affect the accuracy of the design results of the pouring system. For this purpose, castings can be classified in some way. For small and medium-sized castings, they can be classified according to the characteristics of the casting production process, as shown in Table 1. The combination of model clusters can basically reflect the characteristics of castings and the form of casting shrinkage. The cross-sectional dimensions of each part of the pouring system are related to the size of the casting, the combination of model clusters, and the number of pieces per box. Therefore, when designing the process of new castings, targeted calculations should be made based on the characteristics of the castings and the characteristics of the pouring system of similar castings.